| Commit message (Collapse) | Author | Age | Files | Lines |
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KVM x86 misc changes for 6.9:
- Explicitly initialize a variety of on-stack variables in the emulator that
triggered KMSAN false positives (though in fairness in KMSAN, it's comically
difficult to see that the uninitialized memory is never truly consumed).
- Fix the deubgregs ABI for 32-bit KVM, and clean up code related to reading
DR6 and DR7.
- Rework the "force immediate exit" code so that vendor code ultimately
decides how and when to force the exit. This allows VMX to further optimize
handling preemption timer exits, and allows SVM to avoid sending a duplicate
IPI (SVM also has a need to force an exit).
- Fix a long-standing bug where kvm_has_noapic_vcpu could be left elevated if
vCPU creation ultimately failed, and add WARN to guard against similar bugs.
- Provide a dedicated arch hook for checking if a different vCPU was in-kernel
(for directed yield), and simplify the logic for checking if the currently
loaded vCPU is in-kernel.
- Misc cleanups and fixes.
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The SSP fields in the SEV-ES save area were mistakenly named vmplX_ssp
instead of plX_ssp. Rename these to the correct names as defined in the
APM.
Fixes: 6d3b3d34e39e ("KVM: SVM: Update the SEV-ES save area mapping")
Signed-off-by: John Allen <john.allen@amd.com>
Link: https://lore.kernel.org/r/20240227200356.35114-1-john.allen@amd.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
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Add a comment to explain why KVM treats vCPUs with pending interrupts as
in-kernel when a vCPU wants to yield to a vCPU that was preempted while
running in kernel mode.
Link: https://lore.kernel.org/r/20240110003938.490206-5-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
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Directly return the boolean result of whether or not a vCPU has a pending
interrupt instead of effectively doing:
if (true)
return true;
return false;
Reviewed-by: Yuan Yao <yuan.yao@intel.com>
Link: https://lore.kernel.org/r/20240110003938.490206-4-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
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Snapshot preempted_in_kernel using kvm_arch_vcpu_in_kernel() so that the
flag is "accurate" (or rather, consistent and deterministic within KVM)
for guests with protected state, and explicitly use preempted_in_kernel
when checking if a vCPU was preempted in kernel mode instead of bouncing
through kvm_arch_vcpu_in_kernel().
Drop the gnarly logic in kvm_arch_vcpu_in_kernel() that redirects to
preempted_in_kernel if the target vCPU is not the "running", i.e. loaded,
vCPU, as the only reason that code existed was for the directed yield case
where KVM wants to check the CPL of a vCPU that may or may not be loaded
on the current pCPU.
Cc: Like Xu <like.xu.linux@gmail.com>
Reviewed-by: Yuan Yao <yuan.yao@intel.com>
Link: https://lore.kernel.org/r/20240110003938.490206-3-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
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Plumb in a dedicated hook for querying whether or not a vCPU was preempted
in-kernel. Unlike literally every other architecture, x86's VMX can check
if a vCPU is in kernel context if and only if the vCPU is loaded on the
current pCPU.
x86's kvm_arch_vcpu_in_kernel() works around the limitation by querying
kvm_get_running_vcpu() and redirecting to vcpu->arch.preempted_in_kernel
as needed. But that's unnecessary, confusing, and fragile, e.g. x86 has
had at least one bug where KVM incorrectly used a stale
preempted_in_kernel.
No functional change intended.
Reviewed-by: Yuan Yao <yuan.yao@intel.com>
Link: https://lore.kernel.org/r/20240110003938.490206-2-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
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WARN if kvm.ko is unloaded with an elevated kvm_has_noapic_vcpu to guard
against incorrect management of the key, e.g. to detect if KVM fails to
decrement the key in error paths. Because kvm_has_noapic_vcpu is purely
an optimization, in all likelihood KVM could completely botch handling of
kvm_has_noapic_vcpu and no one would notice (which is a good argument for
deleting the key entirely, but that's a problem for another day).
Note, ideally the sanity check would be performance when kvm_usage_count
goes to zero, but adding an arch callback just for this sanity check isn't
at all worth doing.
Link: https://lore.kernel.org/r/20240209222047.394389-3-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
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Move incrementing and decrementing of kvm_has_noapic_vcpu into
kvm_create_lapic() and kvm_free_lapic() respectively to fix a benign bug
where KVM fails to decrement the count if vCPU creation ultimately fails,
e.g. due to a memory allocation failing.
Note, the bug is benign as kvm_has_noapic_vcpu is used purely to optimize
lapic_in_kernel() checks, and that optimization is quite dubious. That,
and practically speaking no setup that cares at all about performance runs
with a userspace local APIC.
Reported-by: Li RongQing <lirongqing@baidu.com>
Cc: Maxim Levitsky <mlevitsk@redhat.com>
Reviewed-by: Xu Yilun <yilun.xu@linux.intel.com>
Link: https://lore.kernel.org/r/20240209222047.394389-2-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
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Now that vmx->req_immediate_exit is used only in the scope of
vmx_vcpu_run(), use force_immediate_exit to detect that KVM should usurp
the VMX preemption to force a VM-Exit and let vendor code fully handle
forcing a VM-Exit.
Opportunsitically drop __kvm_request_immediate_exit() and just have
vendor code call smp_send_reschedule() directly. SVM already does this
when injecting an event while also trying to single-step an IRET, i.e.
it's not exactly secret knowledge that KVM uses a reschedule IPI to force
an exit.
Link: https://lore.kernel.org/r/20240110012705.506918-7-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
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Eat VMX treemption timer exits in the fastpath regardless of whether L1 or
L2 is active. The VM-Exit is 100% KVM-induced, i.e. there is nothing
directly related to the exit that KVM needs to do on behalf of the guest,
thus there is no reason to wait until the slow path to do nothing.
Opportunistically add comments explaining why preemption timer exits for
emulating the guest's APIC timer need to go down the slow path.
Link: https://lore.kernel.org/r/20240110012705.506918-6-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
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Let the fastpath code decide which exits can/can't be handled in the
fastpath when L2 is active, e.g. when KVM generates a VMX preemption
timer exit to forcefully regain control, there is no "work" to be done and
so such exits can be handled in the fastpath regardless of whether L1 or
L2 is active.
Moving the is_guest_mode() check into the fastpath code also makes it
easier to see that L2 isn't allowed to use the fastpath in most cases,
e.g. it's not immediately obvious why handle_fastpath_preemption_timer()
is called from the fastpath and the normal path.
Link: https://lore.kernel.org/r/20240110012705.506918-5-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
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Handle VMX preemption timer VM-Exits due to KVM forcing an exit in the
exit fastpath, i.e. avoid calling back into handle_preemption_timer() for
the same exit. There is no work to be done for forced exits, as the name
suggests the goal is purely to get control back in KVM.
In addition to shaving a few cycles, this will allow cleanly separating
handle_fastpath_preemption_timer() from handle_preemption_timer(), e.g.
it's not immediately obvious why _apparently_ calling
handle_fastpath_preemption_timer() twice on a "slow" exit is necessary:
the "slow" call is necessary to handle exits from L2, which are excluded
from the fastpath by vmx_vcpu_run().
Link: https://lore.kernel.org/r/20240110012705.506918-4-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
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Re-enter the guest in the fast path if VMX preeemption timer VM-Exit was
"spurious", i.e. if KVM "soft disabled" the timer by writing -1u and by
some miracle the timer expired before any other VM-Exit occurred. This is
just an intermediate step to cleaning up the preemption timer handling,
optimizing these types of spurious VM-Exits is not interesting as they are
extremely rare/infrequent.
Link: https://lore.kernel.org/r/20240110012705.506918-3-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
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Annotate the kvm_entry() tracepoint with "immediate exit" when KVM is
forcing a VM-Exit immediately after VM-Enter, e.g. when KVM wants to
inject an event but needs to first complete some other operation.
Knowing that KVM is (or isn't) forcing an exit is useful information when
debugging issues related to event injection.
Suggested-by: Maxim Levitsky <mlevitsk@redhat.com>
Link: https://lore.kernel.org/r/20240110012705.506918-2-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
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Bite the bullet, and open code all direct reads of DR6 and DR7. KVM
currently has a mix of open coded accesses and calls to kvm_get_dr(),
which is confusing and ugly because there's no rhyme or reason as to why
any particular chunk of code uses kvm_get_dr().
The obvious alternative is to force all accesses through kvm_get_dr(),
but it's not at all clear that doing so would be a net positive, e.g. even
if KVM ends up wanting/needing to force all reads through a common helper,
e.g. to play caching games, the cost of reverting this change is likely
lower than the ongoing cost of maintaining weird, arbitrary code.
No functional change intended.
Cc: Mathias Krause <minipli@grsecurity.net>
Reviewed-by: Mathias Krause <minipli@grsecurity.net>
Link: https://lore.kernel.org/r/20240209220752.388160-3-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
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Convert kvm_get_dr()'s output parameter to a return value, and clean up
most of the mess that was created by forcing callers to provide a pointer.
No functional change intended.
Acked-by: Mathias Krause <minipli@grsecurity.net>
Reviewed-by: Mathias Krause <minipli@grsecurity.net>
Link: https://lore.kernel.org/r/20240209220752.388160-2-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
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push and emulate_pop are counterparts. Rename push to emulate_push and
harmonize its function signature with emulate_pop. This should remove
a bit of cognitive load when reading this code.
Signed-off-by: Julian Stecklina <julian.stecklina@cyberus-technology.de>
Link: https://lore.kernel.org/r/20231009092054.556935-2-julian.stecklina@cyberus-technology.de
Signed-off-by: Sean Christopherson <seanjc@google.com>
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Explicitly zero out variables passed to emulate_pop() as output params
to harden against consuming uninitialized data, and to make sanitizers
happy. Many flows that use emulate_pop() pass an "unsigned long" so as
to be able to hold the largest possible operand, but the actual number
of bytes written is usually the word with of the vCPU. E.g. if the vCPU
is in 16-bit or 32-bit mode (on a 64-bit host), the upper portion of the
output param will be uninitialized.
Passing around the uninitialized data is benign, as actual KVM usage of
the output is also tied to the word width, but passing around
uninitialized data makes some sanitizers rightly complain.
Note, initializing the data in emulate_pop() is not a safe alternative,
e.g. it would result in em_leave() clobbering RBP[31:16] if LEAVE were
emulated with a 16-bit stack.
Signed-off-by: Julian Stecklina <julian.stecklina@cyberus-technology.de>
Link: https://lore.kernel.org/r/20231009092054.556935-1-julian.stecklina@cyberus-technology.de
[sean: massage changelog, drop em_popa() variable size change]]
Signed-off-by: Sean Christopherson <seanjc@google.com>
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The MOVBE instruction can come with an operand-size prefix (66h). In
this, case the x86 emulation code returns EMULATION_FAILED.
It turns out that em_movbe can already handle this case and all that
is missing is an entry in respective opcode tables to populate
gprefix->pfx_66.
Signed-off-by: Thomas Prescher <thomas.prescher@cyberus-technology.de>
Signed-off-by: Julian Stecklina <julian.stecklina@cyberus-technology.de>
Acked-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20231212095938.26731-1-julian.stecklina@cyberus-technology.de
Signed-off-by: Sean Christopherson <seanjc@google.com>
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The ioctl()s to get and set KVM's debug registers are broken for 32 bit
kernels as they'd only copy half of the user register state because of a
UAPI and in-kernel type mismatch (__u64 vs. unsigned long; 8 vs. 4
bytes).
This makes it impossible for userland to set anything but DR0 without
resorting to bit folding tricks.
Switch to a loop for copying debug registers that'll implicitly do the
type conversion for us, if needed.
There are likely no users (left) for 32bit KVM, fix the bug nonetheless.
Fixes: a1efbe77c1fd ("KVM: x86: Add support for saving&restoring debug registers")
Signed-off-by: Mathias Krause <minipli@grsecurity.net>
Link: https://lore.kernel.org/r/20240203124522.592778-4-minipli@grsecurity.net
Signed-off-by: Sean Christopherson <seanjc@google.com>
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Use the recently introduced guard(mutex) infrastructure acquire and
automatically release vendor_module_lock when the guard goes out of scope.
Drop the inner __kvm_x86_vendor_init(), its sole purpose was to simplify
releasing vendor_module_lock in error paths.
No functional change intended.
Signed-off-by: Nikolay Borisov <nik.borisov@suse.com>
Reviewed-by: Kai Huang <kai.huang@intel.com>
Link: https://lore.kernel.org/r/20231030141728.1406118-1-nik.borisov@suse.com
[sean: rewrite changelog]
Signed-off-by: Sean Christopherson <seanjc@google.com>
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KVM common MMU changes for 6.9:
- Harden KVM against underflowing the active mmu_notifier invalidation
count, so that "bad" invalidations (usually due to bugs elsehwere in the
kernel) are detected earlier and are less likely to hang the kernel.
- Fix a benign bug in __kvm_mmu_topup_memory_cache() where the object size
and number of objects parameters to kvmalloc_array() were swapped.
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gcc-14 notices that the arguments to kvmalloc_array() are mixed up:
arch/x86/kvm/../../../virt/kvm/kvm_main.c: In function '__kvm_mmu_topup_memory_cache':
arch/x86/kvm/../../../virt/kvm/kvm_main.c:424:53: error: 'kvmalloc_array' sizes specified with 'sizeof' in the earlier argument and not in the later argument [-Werror=calloc-transposed-args]
424 | mc->objects = kvmalloc_array(sizeof(void *), capacity, gfp);
| ^~~~
arch/x86/kvm/../../../virt/kvm/kvm_main.c:424:53: note: earlier argument should specify number of elements, later size of each element
The code still works correctly, but the incorrect order prevents the compiler
from properly tracking the object sizes.
Fixes: 837f66c71207 ("KVM: Allow for different capacities in kvm_mmu_memory_cache structs")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20240212112419.1186065-1-arnd@kernel.org
Signed-off-by: Sean Christopherson <seanjc@google.com>
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When handling the end of an mmu_notifier invalidation, WARN if
mn_active_invalidate_count is already 0 do not decrement it further, i.e.
avoid causing mn_active_invalidate_count to underflow/wrap. In the worst
case scenario, effectively corrupting mn_active_invalidate_count could
cause kvm_swap_active_memslots() to hang indefinitely.
end() calls are *supposed* to be paired with start(), i.e. underflow can
only happen if there is a bug elsewhere in the kernel, but due to lack of
lockdep assertions in the mmu_notifier helpers, it's all too easy for a
bug to go unnoticed for some time, e.g. see the recently introduced
PAGEMAP_SCAN ioctl().
Ideally, mmu_notifiers would incorporate lockdep assertions, but users of
mmu_notifiers aren't required to hold any one specific lock, i.e. adding
the necessary annotations to make lockdep aware of all locks that are
mutally exclusive with mm_take_all_locks() isn't trivial.
Link: https://lore.kernel.org/all/000000000000f6d051060c6785bc@google.com
Link: https://lore.kernel.org/r/20240110004239.491290-1-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
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KVM async page fault changes for 6.9:
- Always flush the async page fault workqueue when a work item is being
removed, especially during vCPU destruction, to ensure that there are no
workers running in KVM code when all references to KVM-the-module are gone,
i.e. to prevent a use-after-free if kvm.ko is unloaded.
- Grab a reference to the VM's mm_struct in the async #PF worker itself instead
of gifting the worker a reference, e.g. so that there's no need to remember
to *conditionally* clean up after the worker.
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Nullify the async #PF worker's local "apf" pointer immediately after the
point where the structure can be freed by the vCPU. The existing comment
is helpful, but easy to overlook as there is no associated code.
Update the comment to clarify that it can be freed by as soon as the lock
is dropped, as "after this point" isn't strictly accurate, nor does it
help understand what prevents the structure from being freed earlier.
Reviewed-by: Xu Yilun <yilun.xu@intel.com>
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Link: https://lore.kernel.org/r/20240110011533.503302-5-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
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Get a reference to the target VM's address space in async_pf_execute()
instead of gifting a reference from kvm_setup_async_pf(). Keeping the
address space alive just to service an async #PF is counter-productive,
i.e. if the process is exiting and all vCPUs are dead, then NOT doing
get_user_pages_remote() and freeing the address space asap is desirable.
Handling the mm reference entirely within async_pf_execute() also
simplifies the async #PF flows as a whole, e.g. it's not immediately
obvious when the worker task vs. the vCPU task is responsible for putting
the gifted mm reference.
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: Xu Yilun <yilun.xu@intel.com>
Link: https://lore.kernel.org/r/20240110011533.503302-4-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
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Put the async #PF worker's reference to the VM's address space as soon as
the worker is done with the mm. This will allow deferring getting a
reference to the worker itself without having to track whether or not
getting a reference succeeded.
Note, if the vCPU is still alive, there is no danger of the worker getting
stuck with tearing down the host page tables, as userspace also holds a
reference (obviously), i.e. there is no risk of delaying the page-present
notification due to triggering the slow path in mmput().
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: Xu Yilun <yilun.xu@intel.com>
Link: https://lore.kernel.org/r/20240110011533.503302-3-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
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Always flush the per-vCPU async #PF workqueue when a vCPU is clearing its
completion queue, e.g. when a VM and all its vCPUs is being destroyed.
KVM must ensure that none of its workqueue callbacks is running when the
last reference to the KVM _module_ is put. Gifting a reference to the
associated VM prevents the workqueue callback from dereferencing freed
vCPU/VM memory, but does not prevent the KVM module from being unloaded
before the callback completes.
Drop the misguided VM refcount gifting, as calling kvm_put_kvm() from
async_pf_execute() if kvm_put_kvm() flushes the async #PF workqueue will
result in deadlock. async_pf_execute() can't return until kvm_put_kvm()
finishes, and kvm_put_kvm() can't return until async_pf_execute() finishes:
WARNING: CPU: 8 PID: 251 at virt/kvm/kvm_main.c:1435 kvm_put_kvm+0x2d/0x320 [kvm]
Modules linked in: vhost_net vhost vhost_iotlb tap kvm_intel kvm irqbypass
CPU: 8 PID: 251 Comm: kworker/8:1 Tainted: G W 6.6.0-rc1-e7af8d17224a-x86/gmem-vm #119
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015
Workqueue: events async_pf_execute [kvm]
RIP: 0010:kvm_put_kvm+0x2d/0x320 [kvm]
Call Trace:
<TASK>
async_pf_execute+0x198/0x260 [kvm]
process_one_work+0x145/0x2d0
worker_thread+0x27e/0x3a0
kthread+0xba/0xe0
ret_from_fork+0x2d/0x50
ret_from_fork_asm+0x11/0x20
</TASK>
---[ end trace 0000000000000000 ]---
INFO: task kworker/8:1:251 blocked for more than 120 seconds.
Tainted: G W 6.6.0-rc1-e7af8d17224a-x86/gmem-vm #119
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/8:1 state:D stack:0 pid:251 ppid:2 flags:0x00004000
Workqueue: events async_pf_execute [kvm]
Call Trace:
<TASK>
__schedule+0x33f/0xa40
schedule+0x53/0xc0
schedule_timeout+0x12a/0x140
__wait_for_common+0x8d/0x1d0
__flush_work.isra.0+0x19f/0x2c0
kvm_clear_async_pf_completion_queue+0x129/0x190 [kvm]
kvm_arch_destroy_vm+0x78/0x1b0 [kvm]
kvm_put_kvm+0x1c1/0x320 [kvm]
async_pf_execute+0x198/0x260 [kvm]
process_one_work+0x145/0x2d0
worker_thread+0x27e/0x3a0
kthread+0xba/0xe0
ret_from_fork+0x2d/0x50
ret_from_fork_asm+0x11/0x20
</TASK>
If kvm_clear_async_pf_completion_queue() actually flushes the workqueue,
then there's no need to gift async_pf_execute() a reference because all
invocations of async_pf_execute() will be forced to complete before the
vCPU and its VM are destroyed/freed. And that in turn fixes the module
unloading bug as __fput() won't do module_put() on the last vCPU reference
until the vCPU has been freed, e.g. if closing the vCPU file also puts the
last reference to the KVM module.
Note that kvm_check_async_pf_completion() may also take the work item off
the completion queue and so also needs to flush the work queue, as the
work will not be seen by kvm_clear_async_pf_completion_queue(). Waiting
on the workqueue could theoretically delay a vCPU due to waiting for the
work to complete, but that's a very, very small chance, and likely a very
small delay. kvm_arch_async_page_present_queued() unconditionally makes a
new request, i.e. will effectively delay entering the guest, so the
remaining work is really just:
trace_kvm_async_pf_completed(addr, cr2_or_gpa);
__kvm_vcpu_wake_up(vcpu);
mmput(mm);
and mmput() can't drop the last reference to the page tables if the vCPU is
still alive, i.e. the vCPU won't get stuck tearing down page tables.
Add a helper to do the flushing, specifically to deal with "wakeup all"
work items, as they aren't actually work items, i.e. are never placed in a
workqueue. Trying to flush a bogus workqueue entry rightly makes
__flush_work() complain (kudos to whoever added that sanity check).
Note, commit 5f6de5cbebee ("KVM: Prevent module exit until all VMs are
freed") *tried* to fix the module refcounting issue by having VMs grab a
reference to the module, but that only made the bug slightly harder to hit
as it gave async_pf_execute() a bit more time to complete before the KVM
module could be unloaded.
Fixes: af585b921e5d ("KVM: Halt vcpu if page it tries to access is swapped out")
Cc: stable@vger.kernel.org
Cc: David Matlack <dmatlack@google.com>
Reviewed-by: Xu Yilun <yilun.xu@intel.com>
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Link: https://lore.kernel.org/r/20240110011533.503302-2-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
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KVM selftests changes for 6.9:
- Add macros to reduce the amount of boilerplate code needed to write "simple"
selftests, and to utilize selftest TAP infrastructure, which is especially
beneficial for KVM selftests with multiple testcases.
- Add basic smoke tests for SEV and SEV-ES, along with a pile of library
support for handling private/encrypted/protected memory.
- Fix benign bugs where tests neglect to close() guest_memfd files.
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Explicitly close() guest_memfd files in various guest_memfd and
private_mem_conversions tests, there's no reason to keep the files open
until the test exits.
Fixes: 8a89efd43423 ("KVM: selftests: Add basic selftest for guest_memfd()")
Fixes: 43f623f350ce ("KVM: selftests: Add x86-only selftest for private memory conversions")
Signed-off-by: Dongli Zhang <dongli.zhang@oracle.com>
Link: https://lore.kernel.org/r/20240227015716.27284-1-dongli.zhang@oracle.com
[sean: massage changelog]
Signed-off-by: Sean Christopherson <seanjc@google.com>
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Extend sev_smoke_test to also run a minimal SEV-ES smoke test so that it's
possible to test KVM's unique VMRUN=>#VMEXIT path for SEV-ES guests
without needing a full blown SEV-ES capable VM, which requires a rather
absurd amount of properly configured collateral.
Punt on proper GHCB and ucall support, and instead use the GHCB MSR
protocol to signal test completion. The most important thing at this
point is to have _any_ kind of testing of KVM's __svm_sev_es_vcpu_run().
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Michael Roth <michael.roth@amd.com>
Cc: Peter Gonda <pgonda@google.com>
Cc: Carlos Bilbao <carlos.bilbao@amd.com>
Tested-by: Carlos Bilbao <carlos.bilbao@amd.com>
Link: https://lore.kernel.org/r/20240223004258.3104051-12-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
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Add a basic smoke test for SEV guests to verify that KVM can launch an
SEV guest and run a few instructions without exploding. To verify that
SEV is indeed enabled, assert that SEV is reported as enabled in
MSR_AMD64_SEV, a.k.a. SEV_STATUS, which cannot be intercepted by KVM
(architecturally enforced).
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Sean Christopherson <seanjc@google.com>
Cc: Vishal Annapurve <vannapurve@google.com>
Cc: Ackerly Tng <ackerleytng@google.com>
cc: Andrew Jones <andrew.jones@linux.dev>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Michael Roth <michael.roth@amd.com>
Suggested-by: Michael Roth <michael.roth@amd.com>
Tested-by: Carlos Bilbao <carlos.bilbao@amd.com>
Signed-off-by: Peter Gonda <pgonda@google.com>
[sean: rename to "sev_smoke_test"]
Link: https://lore.kernel.org/r/20240223004258.3104051-11-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
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Port the existing intra-host SEV(-ES) migration test to the recently added
SEV library, which handles much of the boilerplate needed to create and
configure SEV guests.
Tested-by: Carlos Bilbao <carlos.bilbao@amd.com>
Link: https://lore.kernel.org/r/20240223004258.3104051-10-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
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Add a library/APIs for creating and interfacing with SEV guests, all of
which need some amount of common functionality, e.g. an open file handle
for the SEV driver (/dev/sev), ioctl() wrappers to pass said file handle
to KVM, tracking of the C-bit, etc.
Add an x86-specific hook to initialize address properties, a.k.a. the
location of the C-bit. An arch specific hook is rather gross, but x86
already has a dedicated #ifdef-protected kvm_get_cpu_address_width() hook,
i.e. the ugliest code already exists.
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Sean Christopherson <seanjc@google.com>
Cc: Vishal Annapurve <vannapurve@google.com>
Cc: Ackerly Tng <ackerleytng@google.com>
cc: Andrew Jones <andrew.jones@linux.dev>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Michael Roth <michael.roth@amd.com>
Tested-by: Carlos Bilbao <carlos.bilbao@amd.com>
Originally-by: Michael Roth <michael.roth@amd.com>
Signed-off-by: Peter Gonda <pgonda@google.com>
Co-developed-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/r/20240223004258.3104051-9-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
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Add support for tagging and untagging guest physical address, e.g. to
allow x86's SEV and TDX guests to embed shared vs. private information in
the GPA. SEV (encryption, a.k.a. C-bit) and TDX (shared, a.k.a. S-bit)
steal bits from the guest's physical address space that is consumed by the
CPU metadata, i.e. effectively aliases the "real" GPA.
Implement generic "tagging" so that the shared vs. private metadata can be
managed by x86 without bleeding too many details into common code.
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Sean Christopherson <seanjc@google.com>
Cc: Vishal Annapurve <vannapurve@google.com>
Cc: Ackerly Tng <ackerleytng@google.com>
cc: Andrew Jones <andrew.jones@linux.dev>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Michael Roth <michael.roth@amd.com>
Tested-by: Carlos Bilbao <carlos.bilbao@amd.com>
Originally-by: Michael Roth <michael.roth@amd.com>
Signed-off-by: Peter Gonda <pgonda@google.com>
Link: https://lore.kernel.org/r/20240223004258.3104051-8-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
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Allocate the common ucall pool using vm_vaddr_alloc_shared() so that the
ucall structures will be placed in shared (unencrypted) memory for VMs
with support for protected (encrypted) memory, e.g. x86's SEV.
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Sean Christopherson <seanjc@google.com>
Cc: Vishal Annapurve <vannapurve@google.com>
Cc: Ackerly Tng <ackerleytng@google.com>
cc: Andrew Jones <andrew.jones@linux.dev>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Michael Roth <michael.roth@amd.com>
Tested-by: Carlos Bilbao <carlos.bilbao@amd.com>
Signed-off-by: Peter Gonda <pgonda@google.com>
[sean: massage changelog]
Link: https://lore.kernel.org/r/20240223004258.3104051-7-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
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Test programs may wish to allocate shared vaddrs for things like
sharing memory with the guest. Since protected vms will have their
memory encrypted by default an interface is needed to explicitly
request shared pages.
Implement this by splitting the common code out from vm_vaddr_alloc()
and introducing a new vm_vaddr_alloc_shared().
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Sean Christopherson <seanjc@google.com>
Cc: Vishal Annapurve <vannapurve@google.com>
Cc: Ackerly Tng <ackerleytng@google.com>
cc: Andrew Jones <andrew.jones@linux.dev>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Michael Roth <michael.roth@amd.com>
Reviewed-by: Itaru Kitayama <itaru.kitayama@fujitsu.com>
Tested-by: Carlos Bilbao <carlos.bilbao@amd.com>
Signed-off-by: Michael Roth <michael.roth@amd.com>
Signed-off-by: Peter Gonda <pgonda@google.com>
Link: https://lore.kernel.org/r/20240223004258.3104051-6-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
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Add support for differentiating between protected (a.k.a. private, a.k.a.
encrypted) memory and normal (a.k.a. shared) memory for VMs that support
protected guest memory, e.g. x86's SEV. Provide and manage a common
bitmap for tracking whether a given physical page resides in protected
memory, as support for protected memory isn't x86 specific, i.e. adding a
arch hook would be a net negative now, and in the future.
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Sean Christopherson <seanjc@google.com>
Cc: Vishal Annapurve <vannapurve@google.com>
Cc: Ackerley Tng <ackerleytng@google.com>
cc: Andrew Jones <andrew.jones@linux.dev>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Michael Roth <michael.roth@amd.com>
Reviewed-by: Itaru Kitayama <itaru.kitayama@fujitsu.com>
Tested-by: Carlos Bilbao <carlos.bilbao@amd.com>
Originally-by: Michael Roth <michael.roth@amd.com>
Signed-off-by: Peter Gonda <pgonda@google.com>
Co-developed-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/r/20240223004258.3104051-5-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
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Add sparsebit_for_each_set_range() to allow iterator over a range of set
bits in a range. This will be used by x86 SEV guests to process protected
physical pages (each such page needs to be encrypted _after_ being "added"
to the VM).
Tested-by: Carlos Bilbao <carlos.bilbao@amd.com>
Signed-off-by: Ackerley Tng <ackerleytng@google.com>
[sean: split to separate patch]
Link: https://lore.kernel.org/r/20240223004258.3104051-4-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
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Make all sparsebit struct pointers "const" where appropriate. This will
allow adding a bitmap to track protected/encrypted physical memory that
tests can access in a read-only fashion.
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Sean Christopherson <seanjc@google.com>
Cc: Vishal Annapurve <vannapurve@google.com>
Cc: Ackerley Tng <ackerleytng@google.com>
Cc: Andrew Jones <andrew.jones@linux.dev>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Michael Roth <michael.roth@amd.com>
Tested-by: Carlos Bilbao <carlos.bilbao@amd.com>
Signed-off-by: Michael Roth <michael.roth@amd.com>
Signed-off-by: Peter Gonda <pgonda@google.com>
[sean: massage changelog]
Link: https://lore.kernel.org/r/20240223004258.3104051-3-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
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Carve out space in the @shape passed to the various VM creation helpers to
allow using the shape to control the subtype of VM, e.g. to identify x86's
SEV VMs (which are "regular" VMs as far as KVM is concerned).
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Sean Christopherson <seanjc@google.com>
Cc: Vishal Annapurve <vannapurve@google.com>
Cc: Ackerley Tng <ackerleytng@google.com>
Cc: Andrew Jones <andrew.jones@linux.dev>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Michael Roth <michael.roth@amd.com>
Tested-by: Carlos Bilbao <carlos.bilbao@amd.com>
Link: https://lore.kernel.org/r/20240223004258.3104051-2-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
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Use the kselftest_harness.h interface in this test to get TAP
output, so that it is easier for the user to see what the test
is doing.
Signed-off-by: Thomas Huth <thuth@redhat.com>
Link: https://lore.kernel.org/r/20240208204844.119326-9-thuth@redhat.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
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Use the kvm_test_harness.h interface in this test to get TAP
output, so that it is easier for the user to see what the test
is doing.
Signed-off-by: Thomas Huth <thuth@redhat.com>
Link: https://lore.kernel.org/r/20240208204844.119326-8-thuth@redhat.com
[sean: make host_cap static]
Signed-off-by: Sean Christopherson <seanjc@google.com>
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Use the kvm_test_harness.h interface in this test to get TAP
output, so that it is easier for the user to see what the test
is doing.
Signed-off-by: Thomas Huth <thuth@redhat.com>
Link: https://lore.kernel.org/r/20240208204844.119326-7-thuth@redhat.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
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The sync_regs test currently does not have any output (unless one
of the TEST_ASSERT statement fails), so it's hard to say for a user
whether a certain new sub-test has been included in the binary or
not. Let's make this a little bit more user-friendly and include
some TAP output via the kselftest_harness.h / kvm_test_harness.h
interface.
To be able to use the interface, we have to break up the huge main()
function here in more fine grained parts - then we can use the new
KVM_ONE_VCPU_TEST() macro to define the individual tests. Since these
are run with a separate VM now, we have also to make sure to create
the expected state at the beginning of each test, so some parts grow
a little bit - which should be OK considering that the individual
tests are more self-contained now.
Suggested-by: David Matlack <dmatlack@google.com>
Suggested-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>
Link: https://lore.kernel.org/r/20240208204844.119326-6-thuth@redhat.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
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Most tests are currently not giving any proper output for the user
to see how much sub-tests have already been run, or whether new
sub-tests are part of a binary or not. So it would be good to
support TAP output in the KVM selftests. There is already a nice
framework for this in the kselftest_harness.h header which we can
use. But since we also need a vcpu in most KVM selftests, it also
makes sense to introduce our own wrapper around this which takes
care of creating a VM with one vcpu, so we don't have to repeat
this boilerplate in each and every test. Thus let's introduce
a KVM_ONE_VCPU_TEST() macro here which takes care of this.
Suggested-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/all/Y2v+B3xxYKJSM%2FfH@google.com/
Signed-off-by: Thomas Huth <thuth@redhat.com>
Link: https://lore.kernel.org/r/20240208204844.119326-5-thuth@redhat.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
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Extract the code to set a vCPU's entry point out of vm_arch_vcpu_add() and
into a new API, vcpu_arch_set_entry_point(). Providing a separate API
will allow creating a KVM selftests hardness that can handle tests that
use different entry points for sub-tests, whereas *requiring* the entry
point to be specified at vCPU creation makes it difficult to create a
generic harness, e.g. the boilerplate setup/teardown can't easily create
and destroy the VM and vCPUs.
Signed-off-by: Thomas Huth <thuth@redhat.com>
Link: https://lore.kernel.org/r/20240208204844.119326-4-thuth@redhat.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
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The regs structure just accidentally contains the right values
from the previous test in the spot where we want to change rbx.
It's cleaner if we properly initialize the structure here before
using it.
Suggested-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>
Link: https://lore.kernel.org/r/20240208204844.119326-3-thuth@redhat.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
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In the spots where we are expecting a successful run, we should
use vcpu_run() instead of _vcpu_run() to make sure that the run
did not fail.
Suggested-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>
Link: https://lore.kernel.org/r/20240208204844.119326-2-thuth@redhat.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
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