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* KVM: Ensure lockdep knows about kvm->lock vs. vcpu->mutex ordering ruleDavid Woodhouse2023-01-111-0/+7
| | | | | | | | | | | | | | | Documentation/virt/kvm/locking.rst tells us that kvm->lock is taken outside vcpu->mutex. But that doesn't actually happen very often; it's only in some esoteric cases like migration with AMD SEV. This means that lockdep usually doesn't notice, and doesn't do its job of keeping us honest. Ensure that lockdep *always* knows about the ordering of these two locks, by briefly taking vcpu->mutex in kvm_vm_ioctl_create_vcpu() while kvm->lock is held. Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> Message-Id: <20230111180651.14394-3-dwmw2@infradead.org> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvmLinus Torvalds2022-12-151-27/+80
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Pull kvm updates from Paolo Bonzini: "ARM64: - Enable the per-vcpu dirty-ring tracking mechanism, together with an option to keep the good old dirty log around for pages that are dirtied by something other than a vcpu. - Switch to the relaxed parallel fault handling, using RCU to delay page table reclaim and giving better performance under load. - Relax the MTE ABI, allowing a VMM to use the MAP_SHARED mapping option, which multi-process VMMs such as crosvm rely on (see merge commit 382b5b87a97d: "Fix a number of issues with MTE, such as races on the tags being initialised vs the PG_mte_tagged flag as well as the lack of support for VM_SHARED when KVM is involved. Patches from Catalin Marinas and Peter Collingbourne"). - Merge the pKVM shadow vcpu state tracking that allows the hypervisor to have its own view of a vcpu, keeping that state private. - Add support for the PMUv3p5 architecture revision, bringing support for 64bit counters on systems that support it, and fix the no-quite-compliant CHAIN-ed counter support for the machines that actually exist out there. - Fix a handful of minor issues around 52bit VA/PA support (64kB pages only) as a prefix of the oncoming support for 4kB and 16kB pages. - Pick a small set of documentation and spelling fixes, because no good merge window would be complete without those. s390: - Second batch of the lazy destroy patches - First batch of KVM changes for kernel virtual != physical address support - Removal of a unused function x86: - Allow compiling out SMM support - Cleanup and documentation of SMM state save area format - Preserve interrupt shadow in SMM state save area - Respond to generic signals during slow page faults - Fixes and optimizations for the non-executable huge page errata fix. - Reprogram all performance counters on PMU filter change - Cleanups to Hyper-V emulation and tests - Process Hyper-V TLB flushes from a nested guest (i.e. from a L2 guest running on top of a L1 Hyper-V hypervisor) - Advertise several new Intel features - x86 Xen-for-KVM: - Allow the Xen runstate information to cross a page boundary - Allow XEN_RUNSTATE_UPDATE flag behaviour to be configured - Add support for 32-bit guests in SCHEDOP_poll - Notable x86 fixes and cleanups: - One-off fixes for various emulation flows (SGX, VMXON, NRIPS=0). - Reinstate IBPB on emulated VM-Exit that was incorrectly dropped a few years back when eliminating unnecessary barriers when switching between vmcs01 and vmcs02. - Clean up vmread_error_trampoline() to make it more obvious that params must be passed on the stack, even for x86-64. - Let userspace set all supported bits in MSR_IA32_FEAT_CTL irrespective of the current guest CPUID. - Fudge around a race with TSC refinement that results in KVM incorrectly thinking a guest needs TSC scaling when running on a CPU with a constant TSC, but no hardware-enumerated TSC frequency. - Advertise (on AMD) that the SMM_CTL MSR is not supported - Remove unnecessary exports Generic: - Support for responding to signals during page faults; introduces new FOLL_INTERRUPTIBLE flag that was reviewed by mm folks Selftests: - Fix an inverted check in the access tracking perf test, and restore support for asserting that there aren't too many idle pages when running on bare metal. - Fix build errors that occur in certain setups (unsure exactly what is unique about the problematic setup) due to glibc overriding static_assert() to a variant that requires a custom message. - Introduce actual atomics for clear/set_bit() in selftests - Add support for pinning vCPUs in dirty_log_perf_test. - Rename the so called "perf_util" framework to "memstress". - Add a lightweight psuedo RNG for guest use, and use it to randomize the access pattern and write vs. read percentage in the memstress tests. - Add a common ucall implementation; code dedup and pre-work for running SEV (and beyond) guests in selftests. - Provide a common constructor and arch hook, which will eventually be used by x86 to automatically select the right hypercall (AMD vs. Intel). - A bunch of added/enabled/fixed selftests for ARM64, covering memslots, breakpoints, stage-2 faults and access tracking. - x86-specific selftest changes: - Clean up x86's page table management. - Clean up and enhance the "smaller maxphyaddr" test, and add a related test to cover generic emulation failure. - Clean up the nEPT support checks. - Add X86_PROPERTY_* framework to retrieve multi-bit CPUID values. - Fix an ordering issue in the AMX test introduced by recent conversions to use kvm_cpu_has(), and harden the code to guard against similar bugs in the future. Anything that tiggers caching of KVM's supported CPUID, kvm_cpu_has() in this case, effectively hides opt-in XSAVE features if the caching occurs before the test opts in via prctl(). Documentation: - Remove deleted ioctls from documentation - Clean up the docs for the x86 MSR filter. - Various fixes" * tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (361 commits) KVM: x86: Add proper ReST tables for userspace MSR exits/flags KVM: selftests: Allocate ucall pool from MEM_REGION_DATA KVM: arm64: selftests: Align VA space allocator with TTBR0 KVM: arm64: Fix benign bug with incorrect use of VA_BITS KVM: arm64: PMU: Fix period computation for 64bit counters with 32bit overflow KVM: x86: Advertise that the SMM_CTL MSR is not supported KVM: x86: remove unnecessary exports KVM: selftests: Fix spelling mistake "probabalistic" -> "probabilistic" tools: KVM: selftests: Convert clear/set_bit() to actual atomics tools: Drop "atomic_" prefix from atomic test_and_set_bit() tools: Drop conflicting non-atomic test_and_{clear,set}_bit() helpers KVM: selftests: Use non-atomic clear/set bit helpers in KVM tests perf tools: Use dedicated non-atomic clear/set bit helpers tools: Take @bit as an "unsigned long" in {clear,set}_bit() helpers KVM: arm64: selftests: Enable single-step without a "full" ucall() KVM: x86: fix APICv/x2AVIC disabled when vm reboot by itself KVM: Remove stale comment about KVM_REQ_UNHALT KVM: Add missing arch for KVM_CREATE_DEVICE and KVM_{SET,GET}_DEVICE_ATTR KVM: Reference to kvm_userspace_memory_region in doc and comments KVM: Delete all references to removed KVM_SET_MEMORY_ALIAS ioctl ...
| * Merge remote-tracking branch 'kvm/queue' into HEADPaolo Bonzini2022-12-121-4/+0
| |\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | x86 Xen-for-KVM: * Allow the Xen runstate information to cross a page boundary * Allow XEN_RUNSTATE_UPDATE flag behaviour to be configured * add support for 32-bit guests in SCHEDOP_poll x86 fixes: * One-off fixes for various emulation flows (SGX, VMXON, NRIPS=0). * Reinstate IBPB on emulated VM-Exit that was incorrectly dropped a few years back when eliminating unnecessary barriers when switching between vmcs01 and vmcs02. * Clean up the MSR filter docs. * Clean up vmread_error_trampoline() to make it more obvious that params must be passed on the stack, even for x86-64. * Let userspace set all supported bits in MSR_IA32_FEAT_CTL irrespective of the current guest CPUID. * Fudge around a race with TSC refinement that results in KVM incorrectly thinking a guest needs TSC scaling when running on a CPU with a constant TSC, but no hardware-enumerated TSC frequency. * Advertise (on AMD) that the SMM_CTL MSR is not supported * Remove unnecessary exports Selftests: * Fix an inverted check in the access tracking perf test, and restore support for asserting that there aren't too many idle pages when running on bare metal. * Fix an ordering issue in the AMX test introduced by recent conversions to use kvm_cpu_has(), and harden the code to guard against similar bugs in the future. Anything that tiggers caching of KVM's supported CPUID, kvm_cpu_has() in this case, effectively hides opt-in XSAVE features if the caching occurs before the test opts in via prctl(). * Fix build errors that occur in certain setups (unsure exactly what is unique about the problematic setup) due to glibc overriding static_assert() to a variant that requires a custom message. * Introduce actual atomics for clear/set_bit() in selftests Documentation: * Remove deleted ioctls from documentation * Various fixes
| | * KVM: Remove stale comment about KVM_REQ_UNHALTSean Christopherson2022-12-021-4/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Remove a comment about KVM_REQ_UNHALT being set by kvm_vcpu_check_block() that was missed when KVM_REQ_UNHALT was dropped. Fixes: c59fb1275838 ("KVM: remove KVM_REQ_UNHALT") Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20221201220433.31366-1-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
| * | Merge tag 'kvmarm-6.2' of ↵Paolo Bonzini2022-12-091-12/+53
| |\ \ | | |/ | |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | https://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD KVM/arm64 updates for 6.2 - Enable the per-vcpu dirty-ring tracking mechanism, together with an option to keep the good old dirty log around for pages that are dirtied by something other than a vcpu. - Switch to the relaxed parallel fault handling, using RCU to delay page table reclaim and giving better performance under load. - Relax the MTE ABI, allowing a VMM to use the MAP_SHARED mapping option, which multi-process VMMs such as crosvm rely on. - Merge the pKVM shadow vcpu state tracking that allows the hypervisor to have its own view of a vcpu, keeping that state private. - Add support for the PMUv3p5 architecture revision, bringing support for 64bit counters on systems that support it, and fix the no-quite-compliant CHAIN-ed counter support for the machines that actually exist out there. - Fix a handful of minor issues around 52bit VA/PA support (64kB pages only) as a prefix of the oncoming support for 4kB and 16kB pages. - Add/Enable/Fix a bunch of selftests covering memslots, breakpoints, stage-2 faults and access tracking. You name it, we got it, we probably broke it. - Pick a small set of documentation and spelling fixes, because no good merge window would be complete without those. As a side effect, this tag also drags: - The 'kvmarm-fixes-6.1-3' tag as a dependency to the dirty-ring series - A shared branch with the arm64 tree that repaints all the system registers to match the ARM ARM's naming, and resulting in interesting conflicts
| | * Merge branch kvm-arm64/dirty-ring into kvmarm-master/nextMarc Zyngier2022-12-051-12/+53
| | |\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | * kvm-arm64/dirty-ring: : . : Add support for the "per-vcpu dirty-ring tracking with a bitmap : and sprinkles on top", courtesy of Gavin Shan. : : This branch drags the kvmarm-fixes-6.1-3 tag which was already : merged in 6.1-rc4 so that the branch is in a working state. : . KVM: Push dirty information unconditionally to backup bitmap KVM: selftests: Automate choosing dirty ring size in dirty_log_test KVM: selftests: Clear dirty ring states between two modes in dirty_log_test KVM: selftests: Use host page size to map ring buffer in dirty_log_test KVM: arm64: Enable ring-based dirty memory tracking KVM: Support dirty ring in conjunction with bitmap KVM: Move declaration of kvm_cpu_dirty_log_size() to kvm_dirty_ring.h KVM: x86: Introduce KVM_REQ_DIRTY_RING_SOFT_FULL Signed-off-by: Marc Zyngier <maz@kernel.org>
| | | * KVM: Push dirty information unconditionally to backup bitmapGavin Shan2022-11-121-3/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In mark_page_dirty_in_slot(), we bail out when no running vcpu exists and a running vcpu context is strictly required by architecture. It may cause backwards compatible issue. Currently, saving vgic/its tables is the only known case where no running vcpu context is expected. We may have other unknown cases where no running vcpu context exists and it's reported by the warning message and we bail out without pushing the dirty information to the backup bitmap. For this, the application is going to enable the backup bitmap for the unknown cases. However, the dirty information can't be pushed to the backup bitmap even though the backup bitmap is enabled for those unknown cases in the application, until the unknown cases are added to the allowed list of non-running vcpu context with extra code changes to the host kernel. In order to make the new application, where the backup bitmap has been enabled, to work with the unchanged host, we continue to push the dirty information to the backup bitmap instead of bailing out early. With the added check on 'memslot->dirty_bitmap' to mark_page_dirty_in_slot(), the kernel crash is avoided silently by the combined conditions: no running vcpu context, kvm_arch_allow_write_without_running_vcpu() returns 'true', and the backup bitmap (KVM_CAP_DIRTY_LOG_RING_WITH_BITMAP) isn't enabled yet. Suggested-by: Sean Christopherson <seanjc@google.com> Signed-off-by: Gavin Shan <gshan@redhat.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221112094322.21911-1-gshan@redhat.com
| | | * KVM: Support dirty ring in conjunction with bitmapGavin Shan2022-11-101-9/+52
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | ARM64 needs to dirty memory outside of a VCPU context when VGIC/ITS is enabled. It's conflicting with that ring-based dirty page tracking always requires a running VCPU context. Introduce a new flavor of dirty ring that requires the use of both VCPU dirty rings and a dirty bitmap. The expectation is that for non-VCPU sources of dirty memory (such as the VGIC/ITS on arm64), KVM writes to the dirty bitmap. Userspace should scan the dirty bitmap before migrating the VM to the target. Use an additional capability to advertise this behavior. The newly added capability (KVM_CAP_DIRTY_LOG_RING_WITH_BITMAP) can't be enabled before KVM_CAP_DIRTY_LOG_RING_ACQ_REL on ARM64. In this way, the newly added capability is treated as an extension of KVM_CAP_DIRTY_LOG_RING_ACQ_REL. Suggested-by: Marc Zyngier <maz@kernel.org> Suggested-by: Peter Xu <peterx@redhat.com> Co-developed-by: Oliver Upton <oliver.upton@linux.dev> Signed-off-by: Oliver Upton <oliver.upton@linux.dev> Signed-off-by: Gavin Shan <gshan@redhat.com> Acked-by: Peter Xu <peterx@redhat.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221110104914.31280-4-gshan@redhat.com
| | | * KVM: x86: Introduce KVM_REQ_DIRTY_RING_SOFT_FULLGavin Shan2022-11-101-2/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The VCPU isn't expected to be runnable when the dirty ring becomes soft full, until the dirty pages are harvested and the dirty ring is reset from userspace. So there is a check in each guest's entrace to see if the dirty ring is soft full or not. The VCPU is stopped from running if its dirty ring has been soft full. The similar check will be needed when the feature is going to be supported on ARM64. As Marc Zyngier suggested, a new event will avoid pointless overhead to check the size of the dirty ring ('vcpu->kvm->dirty_ring_size') in each guest's entrance. Add KVM_REQ_DIRTY_RING_SOFT_FULL. The event is raised when the dirty ring becomes soft full in kvm_dirty_ring_push(). The event is only cleared in the check, done in the newly added helper kvm_dirty_ring_check_request(). Since the VCPU is not runnable when the dirty ring becomes soft full, the KVM_REQ_DIRTY_RING_SOFT_FULL event is always set to prevent the VCPU from running until the dirty pages are harvested and the dirty ring is reset by userspace. kvm_dirty_ring_soft_full() becomes a private function with the newly added helper kvm_dirty_ring_check_request(). The alignment for the various event definitions in kvm_host.h is changed to tab character by the way. In order to avoid using 'container_of()', the argument @ring is replaced by @vcpu in kvm_dirty_ring_push(). Link: https://lore.kernel.org/kvmarm/87lerkwtm5.wl-maz@kernel.org Suggested-by: Marc Zyngier <maz@kernel.org> Signed-off-by: Gavin Shan <gshan@redhat.com> Reviewed-by: Peter Xu <peterx@redhat.com> Reviewed-by: Sean Christopherson <seanjc@google.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221110104914.31280-2-gshan@redhat.com
| * | | KVM: x86: avoid memslot check in NX hugepage recovery if it cannot succeedPaolo Bonzini2022-11-181-0/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Since gfn_to_memslot() is relatively expensive, it helps to skip it if it the memslot cannot possibly have dirty logging enabled. In order to do this, add to struct kvm a counter of the number of log-page memslots. While the correct value can only be read with slots_lock taken, the NX recovery thread is content with using an approximate value. Therefore, the counter is an atomic_t. Based on https://lore.kernel.org/kvm/20221027200316.2221027-2-dmatlack@google.com/ by David Matlack. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
| * | | kvm: Add interruptible flag to __gfn_to_pfn_memslot()Peter Xu2022-11-091-11/+17
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Add a new "interruptible" flag showing that the caller is willing to be interrupted by signals during the __gfn_to_pfn_memslot() request. Wire it up with a FOLL_INTERRUPTIBLE flag that we've just introduced. This prepares KVM to be able to respond to SIGUSR1 (for QEMU that's the SIGIPI) even during e.g. handling an userfaultfd page fault. No functional change intended. Signed-off-by: Peter Xu <peterx@redhat.com> Reviewed-by: Sean Christopherson <seanjc@google.com> Message-Id: <20221011195809.557016-4-peterx@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
| * | | kvm: Add KVM_PFN_ERR_SIGPENDINGPeter Xu2022-11-091-0/+2
| |/ / | | | | | | | | | | | | | | | | | | | | | | | | | | | Add a new pfn error to show that we've got a pending signal to handle during hva_to_pfn_slow() procedure (of -EINTR retval). Signed-off-by: Peter Xu <peterx@redhat.com> Reviewed-by: Sean Christopherson <seanjc@google.com> Message-Id: <20221011195809.557016-3-peterx@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* | | KVM: Obey kvm.halt_poll_ns in VMs not using KVM_CAP_HALT_POLLDavid Matlack2022-11-171-3/+24
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Obey kvm.halt_poll_ns in VMs not using KVM_CAP_HALT_POLL on every halt, rather than just sampling the module parameter when the VM is first created. This restore the original behavior of kvm.halt_poll_ns for VMs that have not opted into KVM_CAP_HALT_POLL. Notably, this change restores the ability for admins to disable or change the maximum halt-polling time system wide for VMs not using KVM_CAP_HALT_POLL. Reported-by: Christian Borntraeger <borntraeger@de.ibm.com> Fixes: acd05785e48c ("kvm: add capability for halt polling") Signed-off-by: David Matlack <dmatlack@google.com> Message-Id: <20221117001657.1067231-4-dmatlack@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* | | KVM: Avoid re-reading kvm->max_halt_poll_ns during halt-pollingDavid Matlack2022-11-171-6/+15
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Avoid re-reading kvm->max_halt_poll_ns multiple times during halt-polling except when it is explicitly useful, e.g. to check if the max time changed across a halt. kvm->max_halt_poll_ns can be changed at any time by userspace via KVM_CAP_HALT_POLL. This bug is unlikely to cause any serious side-effects. In the worst case one halt polls for shorter or longer than it should, and then is fixed up on the next halt. Furthmore, this is still possible since kvm->max_halt_poll_ns are not synchronized with halts. Fixes: acd05785e48c ("kvm: add capability for halt polling") Signed-off-by: David Matlack <dmatlack@google.com> Message-Id: <20221117001657.1067231-3-dmatlack@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* | | KVM: Cap vcpu->halt_poll_ns before halting rather than afterDavid Matlack2022-11-171-4/+6
|/ / | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Cap vcpu->halt_poll_ns based on the max halt polling time just before halting, rather than after the last halt. This arguably provides better accuracy if an admin disables halt polling in between halts, although the improvement is nominal. A side-effect of this change is that grow_halt_poll_ns() no longer needs to access vcpu->kvm->max_halt_poll_ns, which will be useful in a future commit where the max halt polling time can come from the module parameter halt_poll_ns instead. Signed-off-by: David Matlack <dmatlack@google.com> Message-Id: <20221117001657.1067231-2-dmatlack@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* | Merge tag 'kvmarm-fixes-6.1-3' of ↵Paolo Bonzini2022-11-061-0/+3
|\| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD * Fix the pKVM stage-1 walker erronously using the stage-2 accessor * Correctly convert vcpu->kvm to a hyp pointer when generating an exception in a nVHE+MTE configuration * Check that KVM_CAP_DIRTY_LOG_* are valid before enabling them * Fix SMPRI_EL1/TPIDR2_EL0 trapping on VHE * Document the boot requirements for FGT when entering the kernel at EL1
| * KVM: Check KVM_CAP_DIRTY_LOG_{RING, RING_ACQ_REL} prior to enabling themGavin Shan2022-10-311-0/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | There are two capabilities related to ring-based dirty page tracking: KVM_CAP_DIRTY_LOG_RING and KVM_CAP_DIRTY_LOG_RING_ACQ_REL. Both are supported by x86. However, arm64 supports KVM_CAP_DIRTY_LOG_RING_ACQ_REL only when the feature is supported on arm64. The userspace doesn't have to enable the advertised capability, meaning KVM_CAP_DIRTY_LOG_RING can be enabled on arm64 by userspace and it's wrong. Fix it by double checking if the capability has been advertised prior to enabling it. It's rejected to enable the capability if it hasn't been advertised. Fixes: 17601bfed909 ("KVM: Add KVM_CAP_DIRTY_LOG_RING_ACQ_REL capability and config option") Reported-by: Sean Christopherson <seanjc@google.com> Suggested-by: Sean Christopherson <seanjc@google.com> Signed-off-by: Gavin Shan <gshan@redhat.com> Reviewed-by: Oliver Upton <oliver.upton@linux.dev> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221031003621.164306-4-gshan@redhat.com
* | KVM: debugfs: Return retval of simple_attr_open() if it failsHou Wenlong2022-10-271-7/+6
|/ | | | | | | | | | | | | Although simple_attr_open() fails only with -ENOMEM with current code base, it would be nicer to return retval of simple_attr_open() directly in kvm_debugfs_open(). No functional change intended. Signed-off-by: Hou Wenlong <houwenlong.hwl@antgroup.com> Message-Id: <69d64d93accd1f33691b8a383ae555baee80f943.1665975828.git.houwenlong.hwl@antgroup.com> Cc: stable@vger.kernel.org Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* kvm: Add support for arch compat vm ioctlsAlexander Graf2022-10-221-0/+11
| | | | | | | | | | | We will introduce the first architecture specific compat vm ioctl in the next patch. Add all necessary boilerplate to allow architectures to override compat vm ioctls when necessary. Signed-off-by: Alexander Graf <graf@amazon.com> Message-Id: <20221017184541.2658-2-graf@amazon.com> Cc: stable@vger.kernel.org Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* Merge tag 'kvmarm-6.1' of ↵Paolo Bonzini2022-10-031-1/+8
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD KVM/arm64 updates for v6.1 - Fixes for single-stepping in the presence of an async exception as well as the preservation of PSTATE.SS - Better handling of AArch32 ID registers on AArch64-only systems - Fixes for the dirty-ring API, allowing it to work on architectures with relaxed memory ordering - Advertise the new kvmarm mailing list - Various minor cleanups and spelling fixes
| * KVM: Add KVM_CAP_DIRTY_LOG_RING_ACQ_REL capability and config optionMarc Zyngier2022-09-291-1/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In order to differenciate between architectures that require no extra synchronisation when accessing the dirty ring and those who do, add a new capability (KVM_CAP_DIRTY_LOG_RING_ACQ_REL) that identify the latter sort. TSO architectures can obviously advertise both, while relaxed architectures must only advertise the ACQ_REL version. This requires some configuration symbol rejigging, with HAVE_KVM_DIRTY_RING being only indirectly selected by two top-level config symbols: - HAVE_KVM_DIRTY_RING_TSO for strongly ordered architectures (x86) - HAVE_KVM_DIRTY_RING_ACQ_REL for weakly ordered architectures (arm64) Suggested-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Reviewed-by: Gavin Shan <gshan@redhat.com> Reviewed-by: Peter Xu <peterx@redhat.com> Link: https://lore.kernel.org/r/20220926145120.27974-3-maz@kernel.org
* | KVM: remove KVM_REQ_UNHALTPaolo Bonzini2022-09-261-3/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | KVM_REQ_UNHALT is now unnecessary because it is replaced by the return value of kvm_vcpu_block/kvm_vcpu_halt. Remove it. No functional change intended. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Sean Christopherson <seanjc@google.com> Acked-by: Marc Zyngier <maz@kernel.org> Message-Id: <20220921003201.1441511-13-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* | KVM: fix memoryleak in kvm_init()Miaohe Lin2022-09-261-3/+2
|/ | | | | | | | | | | | When alloc_cpumask_var_node() fails for a certain cpu, there might be some allocated cpumasks for percpu cpu_kick_mask. We should free these cpumasks or memoryleak will occur. Fixes: baff59ccdc65 ("KVM: Pre-allocate cpumasks for kvm_make_all_cpus_request_except()") Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> Link: https://lore.kernel.org/r/20220823063414.59778-1-linmiaohe@huawei.com Signed-off-by: Sean Christopherson <seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* KVM: Drop unnecessary initialization of "ops" in kvm_ioctl_create_device()Li kunyu2022-08-191-1/+1
| | | | | | | | | The variable is initialized but it is only used after its assignment. Reviewed-by: Sean Christopherson <seanjc@google.com> Signed-off-by: Li kunyu <kunyu@nfschina.com> Message-Id: <20220819021535.483702-1-kunyu@nfschina.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* KVM: Drop unnecessary initialization of "npages" in hva_to_pfn_slow()Li kunyu2022-08-191-1/+1
| | | | | | | | | The variable is initialized but it is only used after its assignment. Reviewed-by: Sean Christopherson <seanjc@google.com> Signed-off-by: Li kunyu <kunyu@nfschina.com> Message-Id: <20220819022804.483914-1-kunyu@nfschina.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* KVM: Rename mmu_notifier_* to mmu_invalidate_*Chao Peng2022-08-191-25/+27
| | | | | | | | | | | | | | | | | | | | | | | | | | | The motivation of this renaming is to make these variables and related helper functions less mmu_notifier bound and can also be used for non mmu_notifier based page invalidation. mmu_invalidate_* was chosen to better describe the purpose of 'invalidating' a page that those variables are used for. - mmu_notifier_seq/range_start/range_end are renamed to mmu_invalidate_seq/range_start/range_end. - mmu_notifier_retry{_hva} helper functions are renamed to mmu_invalidate_retry{_hva}. - mmu_notifier_count is renamed to mmu_invalidate_in_progress to avoid confusion with mn_active_invalidate_count. - While here, also update kvm_inc/dec_notifier_count() to kvm_mmu_invalidate_begin/end() to match the change for mmu_notifier_count. No functional change intended. Signed-off-by: Chao Peng <chao.p.peng@linux.intel.com> Message-Id: <20220816125322.1110439-3-chao.p.peng@linux.intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* KVM: Move coalesced MMIO initialization (back) into kvm_create_vm()Sean Christopherson2022-08-191-5/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | Invoke kvm_coalesced_mmio_init() from kvm_create_vm() now that allocating and initializing coalesced MMIO objects is separate from registering any associated devices. Moving coalesced MMIO cleans up the last oddity where KVM does VM creation/initialization after kvm_create_vm(), and more importantly after kvm_arch_post_init_vm() is called and the VM is added to the global vm_list, i.e. after the VM is fully created as far as KVM is concerned. Originally, kvm_coalesced_mmio_init() was called by kvm_create_vm(), but the original implementation was completely devoid of error handling. Commit 6ce5a090a9a0 ("KVM: coalesced_mmio: fix kvm_coalesced_mmio_init()'s error handling" fixed the various bugs, and in doing so rightly moved the call to after kvm_create_vm() because kvm_coalesced_mmio_init() also registered the coalesced MMIO device. Commit 2b3c246a682c ("KVM: Make coalesced mmio use a device per zone") cleaned up that mess by having each zone register a separate device, i.e. moved device registration to its logical home in kvm_vm_ioctl_register_coalesced_mmio(). As a result, kvm_coalesced_mmio_init() is now a "pure" initialization helper and can be safely called from kvm_create_vm(). Opportunstically drop the #ifdef, KVM provides stubs for kvm_coalesced_mmio_{init,free}() when CONFIG_KVM_MMIO=n (s390). Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20220816053937.2477106-4-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* KVM: Unconditionally get a ref to /dev/kvm module when creating a VMSean Christopherson2022-08-191-10/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Unconditionally get a reference to the /dev/kvm module when creating a VM instead of using try_get_module(), which will fail if the module is in the process of being forcefully unloaded. The error handling when try_get_module() fails doesn't properly unwind all that has been done, e.g. doesn't call kvm_arch_pre_destroy_vm() and doesn't remove the VM from the global list. Not removing VMs from the global list tends to be fatal, e.g. leads to use-after-free explosions. The obvious alternative would be to add proper unwinding, but the justification for using try_get_module(), "rmmod --wait", is completely bogus as support for "rmmod --wait", i.e. delete_module() without O_NONBLOCK, was removed by commit 3f2b9c9cdf38 ("module: remove rmmod --wait option.") nearly a decade ago. It's still possible for try_get_module() to fail due to the module dying (more like being killed), as the module will be tagged MODULE_STATE_GOING by "rmmod --force", i.e. delete_module(..., O_TRUNC), but playing nice with forced unloading is an exercise in futility and gives a falsea sense of security. Using try_get_module() only prevents acquiring _new_ references, it doesn't magically put the references held by other VMs, and forced unloading doesn't wait, i.e. "rmmod --force" on KVM is all but guaranteed to cause spectacular fireworks; the window where KVM will fail try_get_module() is tiny compared to the window where KVM is building and running the VM with an elevated module refcount. Addressing KVM's inability to play nice with "rmmod --force" is firmly out-of-scope. Forcefully unloading any module taints kernel (for obvious reasons) _and_ requires the kernel to be built with CONFIG_MODULE_FORCE_UNLOAD=y, which is off by default and comes with the amusing disclaimer that it's "mainly for kernel developers and desperate users". In other words, KVM is free to scoff at bug reports due to using "rmmod --force" while VMs may be running. Fixes: 5f6de5cbebee ("KVM: Prevent module exit until all VMs are freed") Cc: stable@vger.kernel.org Cc: David Matlack <dmatlack@google.com> Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20220816053937.2477106-3-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* KVM: Properly unwind VM creation if creating debugfs failsSean Christopherson2022-08-191-8/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Properly unwind VM creation if kvm_create_vm_debugfs() fails. A recent change to invoke kvm_create_vm_debug() in kvm_create_vm() was led astray by buggy try_get_module() handling adding by commit 5f6de5cbebee ("KVM: Prevent module exit until all VMs are freed"). The debugfs error path effectively inherits the bad error path of try_module_get(), e.g. KVM leaves the to-be-free VM on vm_list even though KVM appears to do the right thing by calling module_put() and falling through. Opportunistically hoist kvm_create_vm_debugfs() above the call to kvm_arch_post_init_vm() so that the "post-init" arch hook is actually invoked after the VM is initialized (ignoring kvm_coalesced_mmio_init() for the moment). x86 is the only non-nop implementation of the post-init hook, and it doesn't allocate/initialize any objects that are reachable via debugfs code (spawns a kthread worker for the NX huge page mitigation). Leave the buggy try_get_module() alone for now, it will be fixed in a separate commit. Fixes: b74ed7a68ec1 ("KVM: Actually create debugfs in kvm_create_vm()") Reported-by: syzbot+744e173caec2e1627ee0@syzkaller.appspotmail.com Cc: Oliver Upton <oliver.upton@linux.dev> Signed-off-by: Sean Christopherson <seanjc@google.com> Reviewed-by: Oliver Upton <oliver.upton@linux.dev> Message-Id: <20220816053937.2477106-2-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* KVM: Actually create debugfs in kvm_create_vm()Oliver Upton2022-08-101-17/+19
| | | | | | | | | | | | | | | | | | | | | Doing debugfs creation after vm creation leaves things in a quasi-initialized state for a while. This is further complicated by the fact that we tear down debugfs from kvm_destroy_vm(). Align debugfs and stats init/destroy with the vm init/destroy pattern to avoid any headaches. Note the fix for a benign mistake in error handling for calls to kvm_arch_create_vm_debugfs() rolled in. Since all implementations of the function return 0 unconditionally it isn't actually a bug at the moment. Lastly, tear down debugfs/stats data in the kvm_create_vm_debugfs() error path. Previously it was safe to assume that kvm_destroy_vm() would take out the garbage, that is no longer the case. Signed-off-by: Oliver Upton <oupton@google.com> Message-Id: <20220720092259.3491733-6-oliver.upton@linux.dev> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* KVM: Pass the name of the VM fd to kvm_create_vm_debugfs()Oliver Upton2022-08-101-3/+6
| | | | | | | | | | | | | | | At the time the VM fd is used in kvm_create_vm_debugfs(), the fd has been allocated but not yet installed. It is only really useful as an identifier in strings for the VM (such as debugfs). Treat it exactly as such by passing the string name of the fd to kvm_create_vm_debugfs(), futureproofing against possible misuse of the VM fd. Suggested-by: Sean Christopherson <seanjc@google.com> Signed-off-by: Oliver Upton <oupton@google.com> Message-Id: <20220720092259.3491733-5-oliver.upton@linux.dev> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* KVM: Get an fd before creating the VMOliver Upton2022-08-101-13/+17
| | | | | | | | | | Allocate a VM's fd at the very beginning of kvm_dev_ioctl_create_vm() so that KVM can use the fd value to generate strigns, e.g. for debugfs, when creating and initializing the VM. Signed-off-by: Oliver Upton <oupton@google.com> Message-Id: <20220720092259.3491733-4-oliver.upton@linux.dev> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* KVM: Shove vcpu stats_id init into kvm_vcpu_init()Oliver Upton2022-08-101-4/+4
| | | | | | | | | | | Initialize stats_id alongside other kvm_vcpu fields to make it more difficult to unintentionally access stats_id before it's set. No functional change intended. Signed-off-by: Oliver Upton <oupton@google.com> Message-Id: <20220720092259.3491733-3-oliver.upton@linux.dev> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* KVM: Shove vm stats_id init into kvm_create_vm()Oliver Upton2022-08-101-3/+3
| | | | | | | | | | | | | Initialize stats_id alongside other struct kvm fields to make it more difficult to unintentionally access stats_id before it's set. While at it, move the format string to the first line of the call and fix the indentation of the second line. No functional change intended. Signed-off-by: Oliver Upton <oupton@google.com> Message-Id: <20220720092259.3491733-2-oliver.upton@linux.dev> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* Merge remote-tracking branch 'kvm/next' into kvm-next-5.20Paolo Bonzini2022-08-011-57/+162
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | KVM/s390, KVM/x86 and common infrastructure changes for 5.20 x86: * Permit guests to ignore single-bit ECC errors * Fix races in gfn->pfn cache refresh; do not pin pages tracked by the cache * Intel IPI virtualization * Allow getting/setting pending triple fault with KVM_GET/SET_VCPU_EVENTS * PEBS virtualization * Simplify PMU emulation by just using PERF_TYPE_RAW events * More accurate event reinjection on SVM (avoid retrying instructions) * Allow getting/setting the state of the speaker port data bit * Refuse starting the kvm-intel module if VM-Entry/VM-Exit controls are inconsistent * "Notify" VM exit (detect microarchitectural hangs) for Intel * Cleanups for MCE MSR emulation s390: * add an interface to provide a hypervisor dump for secure guests * improve selftests to use TAP interface * enable interpretive execution of zPCI instructions (for PCI passthrough) * First part of deferred teardown * CPU Topology * PV attestation * Minor fixes Generic: * new selftests API using struct kvm_vcpu instead of a (vm, id) tuple x86: * Use try_cmpxchg64 instead of cmpxchg64 * Bugfixes * Ignore benign host accesses to PMU MSRs when PMU is disabled * Allow disabling KVM's "MONITOR/MWAIT are NOPs!" behavior * x86/MMU: Allow NX huge pages to be disabled on a per-vm basis * Port eager page splitting to shadow MMU as well * Enable CMCI capability by default and handle injected UCNA errors * Expose pid of vcpu threads in debugfs * x2AVIC support for AMD * cleanup PIO emulation * Fixes for LLDT/LTR emulation * Don't require refcounted "struct page" to create huge SPTEs x86 cleanups: * Use separate namespaces for guest PTEs and shadow PTEs bitmasks * PIO emulation * Reorganize rmap API, mostly around rmap destruction * Do not workaround very old KVM bugs for L0 that runs with nesting enabled * new selftests API for CPUID
| * KVM: debugfs: expose pid of vcpu threadsVineeth Pillai2022-06-241-2/+13
| | | | | | | | | | | | | | | | | | | | Add a new debugfs file to expose the pid of each vcpu threads. This is very helpful for userland tools to get the vcpu pids without worrying about thread naming conventions of the VMM. Signed-off-by: Vineeth Pillai (Google) <vineeth@bitbyteword.org> Message-Id: <20220523190327.2658-1-vineeth@bitbyteword.org> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
| * KVM: Allow for different capacities in kvm_mmu_memory_cache structsDavid Matlack2022-06-241-3/+30
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Allow the capacity of the kvm_mmu_memory_cache struct to be chosen at declaration time rather than being fixed for all declarations. This will be used in a follow-up commit to declare an cache in x86 with a capacity of 512+ objects without having to increase the capacity of all caches in KVM. This change requires each cache now specify its capacity at runtime, since the cache struct itself no longer has a fixed capacity known at compile time. To protect against someone accidentally defining a kvm_mmu_memory_cache struct directly (without the extra storage), this commit includes a WARN_ON() in kvm_mmu_topup_memory_cache(). In order to support different capacities, this commit changes the objects pointer array to be dynamically allocated the first time the cache is topped-up. While here, opportunistically clean up the stack-allocated kvm_mmu_memory_cache structs in riscv and arm64 to use designated initializers. No functional change intended. Reviewed-by: Marc Zyngier <maz@kernel.org> Signed-off-by: David Matlack <dmatlack@google.com> Message-Id: <20220516232138.1783324-22-dmatlack@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
| * KVM: Do not zero initialize 'pfn' in hva_to_pfn()Sean Christopherson2022-06-201-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Drop the unnecessary initialization of the local 'pfn' variable in hva_to_pfn(). First and foremost, '0' is not an invalid pfn, it's a perfectly valid pfn on most architectures. I.e. if hva_to_pfn() were to return an "uninitializd" pfn, it would actually be interpeted as a legal pfn by most callers. Second, hva_to_pfn() can't return an uninitialized pfn as hva_to_pfn() explicitly sets pfn to an error value (or returns an error value directly) if a helper returns failure, and all helpers set the pfn on success. The zeroing of 'pfn' was introduced by commit 2fc843117d64 ("KVM: reorganize hva_to_pfn"), probably to avoid "uninitialized variable" warnings on statements that return pfn. However, no compiler seems to produce them, making the initialization unnecessary. Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20220429010416.2788472-2-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
| * KVM: Rename/refactor kvm_is_reserved_pfn() to kvm_pfn_to_refcounted_page()Sean Christopherson2022-06-201-14/+52
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Rename and refactor kvm_is_reserved_pfn() to kvm_pfn_to_refcounted_page() to better reflect what KVM is actually checking, and to eliminate extra pfn_to_page() lookups. The kvm_release_pfn_*() an kvm_try_get_pfn() helpers in particular benefit from "refouncted" nomenclature, as it's not all that obvious why KVM needs to get/put refcounts for some PG_reserved pages (ZERO_PAGE and ZONE_DEVICE). Add a comment to call out that the list of exceptions to PG_reserved is all but guaranteed to be incomplete. The list has mostly been compiled by people throwing noodles at KVM and finding out they stick a little too well, e.g. the ZERO_PAGE's refcount overflowed and ZONE_DEVICE pages didn't get freed. No functional change intended. Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20220429010416.2788472-10-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
| * KVM: Take a 'struct page', not a pfn in kvm_is_zone_device_page()Sean Christopherson2022-06-201-4/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Operate on a 'struct page' instead of a pfn when checking if a page is a ZONE_DEVICE page, and rename the helper accordingly. Generally speaking, KVM doesn't actually care about ZONE_DEVICE memory, i.e. shouldn't do anything special for ZONE_DEVICE memory. Rather, KVM wants to treat ZONE_DEVICE memory like regular memory, and the need to identify ZONE_DEVICE memory only arises as an exception to PG_reserved pages. In other words, KVM should only ever check for ZONE_DEVICE memory after KVM has already verified that there is a struct page associated with the pfn. No functional change intended. Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20220429010416.2788472-9-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
| * KVM: Remove kvm_vcpu_gfn_to_page() and kvm_vcpu_gpa_to_page()Sean Christopherson2022-06-201-20/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | Drop helpers to convert a gfn/gpa to a 'struct page' in the context of a vCPU. KVM doesn't require that guests be backed by 'struct page' memory, thus any use of helpers that assume 'struct page' is bound to be flawed, as was the case for the recently removed last user in x86's nested VMX. No functional change intended. Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20220429010416.2788472-8-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
| * KVM: Don't WARN if kvm_pfn_to_page() encounters a "reserved" pfnSean Christopherson2022-06-201-3/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Drop a WARN_ON() if kvm_pfn_to_page() encounters a "reserved" pfn, which in this context means a struct page that has PG_reserved but is not a/the ZERO_PAGE and is not a ZONE_DEVICE page. The usage, via gfn_to_page(), in x86 is safe as gfn_to_page() is used only to retrieve a page from KVM-controlled memslot, but the usage in PPC and s390 operates on arbitrary gfns and thus memslots that can be backed by incompatible memory. Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20220429010416.2788472-7-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
| * KVM: Avoid pfn_to_page() and vice versa when releasing pagesSean Christopherson2022-06-201-21/+43
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Invert the order of KVM's page/pfn release helpers so that the "inner" helper operates on a page instead of a pfn. As pointed out by Linus[*], converting between struct page and a pfn isn't necessarily cheap, and that's not even counting the overhead of is_error_noslot_pfn() and kvm_is_reserved_pfn(). Even if the checks were dirt cheap, there's no reason to convert from a page to a pfn and back to a page, just to mark the page dirty/accessed or to put a reference to the page. Opportunistically drop a stale declaration of kvm_set_page_accessed() from kvm_host.h (there was no implementation). No functional change intended. [*] https://lore.kernel.org/all/CAHk-=wifQimj2d6npq-wCi5onYPjzQg4vyO4tFcPJJZr268cRw@mail.gmail.com Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20220429010416.2788472-5-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
| * KVM: Don't set Accessed/Dirty bits for ZERO_PAGESean Christopherson2022-06-201-2/+14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Don't set Accessed/Dirty bits for a struct page with PG_reserved set, i.e. don't set A/D bits for the ZERO_PAGE. The ZERO_PAGE (or pages depending on the architecture) should obviously never be written, and similarly there's no point in marking it accessed as the page will never be swapped out or reclaimed. The comment in page-flags.h is quite clear that PG_reserved pages should be managed only by their owner, and strictly following that mandate also simplifies KVM's logic. Fixes: 7df003c85218 ("KVM: fix overflow of zero page refcount with ksm running") Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20220429010416.2788472-4-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
| * KVM: Drop bogus "pfn != 0" guard from kvm_release_pfn()Sean Christopherson2022-06-201-3/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Remove a check from kvm_release_pfn() to bail if the provided @pfn is zero. Zero is a perfectly valid pfn on most architectures, and should not be used to indicate an error or an invalid pfn. The bogus check was added by commit 917248144db5 ("x86/kvm: Cache gfn to pfn translation"), which also did the bad thing of zeroing the pfn and gfn to mark a cache invalid. Thankfully, that bad behavior was axed by commit 357a18ad230f ("KVM: Kill kvm_map_gfn() / kvm_unmap_gfn() and gfn_to_pfn_cache"). Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20220429010416.2788472-3-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
| * KVM: Rename ack_flush() to ack_kick()Lai Jiangshan2022-06-151-2/+2
| | | | | | | | | | | | | | | | Make it use the same verb as in kvm_kick_many_cpus(). Signed-off-by: Lai Jiangshan <jiangshan.ljs@antgroup.com> Message-Id: <20220605063417.308311-5-jiangshanlai@gmail.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
| * Merge branch 'kvm-5.20-early'Paolo Bonzini2022-06-091-4/+15
| |\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | s390: * add an interface to provide a hypervisor dump for secure guests * improve selftests to show tests x86: * Intel IPI virtualization * Allow getting/setting pending triple fault with KVM_GET/SET_VCPU_EVENTS * PEBS virtualization * Simplify PMU emulation by just using PERF_TYPE_RAW events * More accurate event reinjection on SVM (avoid retrying instructions) * Allow getting/setting the state of the speaker port data bit * Rewrite gfn-pfn cache refresh * Refuse starting the module if VM-Entry/VM-Exit controls are inconsistent * "Notify" VM exit
| | * KVM: Move kvm_arch_vcpu_precreate() under kvm->lockZeng Guang2022-06-081-4/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | kvm_arch_vcpu_precreate() targets to handle arch specific VM resource to be prepared prior to the actual creation of vCPU. For example, x86 platform may need do per-VM allocation based on max_vcpu_ids at the first vCPU creation. It probably leads to concurrency control on this allocation as multiple vCPU creation could happen simultaneously. From the architectual point of view, it's necessary to execute kvm_arch_vcpu_precreate() under protect of kvm->lock. Currently only arm64, x86 and s390 have non-nop implementations at the stage of vCPU pre-creation. Remove the lock acquiring in s390's design and make sure all architecture can run kvm_arch_vcpu_precreate() safely under kvm->lock without recrusive lock issue. Suggested-by: Sean Christopherson <seanjc@google.com> Signed-off-by: Zeng Guang <guang.zeng@intel.com> Message-Id: <20220419154409.11842-1-guang.zeng@intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
| | * Merge branch 'kvm-5.20-early-patches' into HEADPaolo Bonzini2022-06-071-0/+9
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| | | * KVM: Fix multiple races in gfn=>pfn cache refreshSean Christopherson2022-05-251-0/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Rework the gfn=>pfn cache (gpc) refresh logic to address multiple races between the cache itself, and between the cache and mmu_notifier events. The existing refresh code attempts to guard against races with the mmu_notifier by speculatively marking the cache valid, and then marking it invalid if a mmu_notifier invalidation occurs. That handles the case where an invalidation occurs between dropping and re-acquiring gpc->lock, but it doesn't handle the scenario where the cache is refreshed after the cache was invalidated by the notifier, but before the notifier elevates mmu_notifier_count. The gpc refresh can't use the "retry" helper as its invalidation occurs _before_ mmu_notifier_count is elevated and before mmu_notifier_range_start is set/updated. CPU0 CPU1 ---- ---- gfn_to_pfn_cache_invalidate_start() | -> gpc->valid = false; kvm_gfn_to_pfn_cache_refresh() | |-> gpc->valid = true; hva_to_pfn_retry() | -> acquire kvm->mmu_lock kvm->mmu_notifier_count == 0 mmu_seq == kvm->mmu_notifier_seq drop kvm->mmu_lock return pfn 'X' acquire kvm->mmu_lock kvm_inc_notifier_count() drop kvm->mmu_lock() kernel frees pfn 'X' kvm_gfn_to_pfn_cache_check() | |-> gpc->valid == true caller accesses freed pfn 'X' Key off of mn_active_invalidate_count to detect that a pfncache refresh needs to wait for an in-progress mmu_notifier invalidation. While mn_active_invalidate_count is not guaranteed to be stable, it is guaranteed to be elevated prior to an invalidation acquiring gpc->lock, so either the refresh will see an active invalidation and wait, or the invalidation will run after the refresh completes. Speculatively marking the cache valid is itself flawed, as a concurrent kvm_gfn_to_pfn_cache_check() would see a valid cache with stale pfn/khva values. The KVM Xen use case explicitly allows/wants multiple users; even though the caches are allocated per vCPU, __kvm_xen_has_interrupt() can read a different vCPU (or vCPUs). Address this race by invalidating the cache prior to dropping gpc->lock (this is made possible by fixing the above mmu_notifier race). Complicating all of this is the fact that both the hva=>pfn resolution and mapping of the kernel address can sleep, i.e. must be done outside of gpc->lock. Fix the above races in one fell swoop, trying to fix each individual race is largely pointless and essentially impossible to test, e.g. closing one hole just shifts the focus to the other hole. Fixes: 982ed0de4753 ("KVM: Reinstate gfn_to_pfn_cache with invalidation support") Cc: stable@vger.kernel.org Cc: David Woodhouse <dwmw@amazon.co.uk> Cc: Mingwei Zhang <mizhang@google.com> Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20220429210025.3293691-8-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-27 10:10:46 +0000