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* KVM: MIPS: Add VZ support to build systemJames Hogan2017-03-282-3/+32
| | | | | | | | | | | | | | | | | | | Add support for the MIPS Virtualization (VZ) ASE to the MIPS KVM build system. For now KVM can only be configured for T&E or VZ and not both, but the design of the user facing APIs support the possibility of having both available, so this could change in future. Note that support for various optional guest features (some of which can't be turned off) are implemented in immediately following commits, so although it should now be possible to build VZ support, it may not work yet on your hardware. Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: "Radim Krčmář" <rkrcmar@redhat.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: linux-mips@linux-mips.org Cc: kvm@vger.kernel.org
* KVM: MIPS: Implement VZ supportJames Hogan2017-03-286-0/+2433
| | | | | | | | | | | | | | | | | | | | | Add the main support for the MIPS Virtualization ASE (A.K.A. VZ) to MIPS KVM. The bulk of this work is in vz.c, with various new state and definitions elsewhere. Enough is implemented to be able to run on a minimal VZ core. Further patches will fill out support for guest features which are optional or can be disabled. Signed-off-by: James Hogan <james.hogan@imgtec.com> Acked-by: Ralf Baechle <ralf@linux-mips.org> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: "Radim Krčmář" <rkrcmar@redhat.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: linux-mips@linux-mips.org Cc: kvm@vger.kernel.org Cc: linux-doc@vger.kernel.org
* KVM: MIPS: Update exit handler for VZJames Hogan2017-03-281-13/+18
| | | | | | | | | | | | | | | | | | | | The general guest exit handler needs a few tweaks for VZ compared to trap & emulate, which for now are made directly depending on CONFIG_KVM_MIPS_VZ: - There is no need to re-enable the hardware page table walker (HTW), as it can be left enabled during guest mode operation with VZ. - There is no need to perform a privilege check, as any guest privilege violations should have already been detected by the hardware and triggered the appropriate guest exception. Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: "Radim Krčmář" <rkrcmar@redhat.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: linux-mips@linux-mips.org Cc: kvm@vger.kernel.org
* KVM: MIPS/Emulate: Drop CACHE emulation for VZJames Hogan2017-03-281-0/+2
| | | | | | | | | | | | | Ifdef out the trap & emulate CACHE instruction emulation functions for VZ. We will provide separate CACHE instruction emulation in vz.c, and we need to avoid linker errors due to the use of T&E specific MMU helpers. Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: "Radim Krčmář" <rkrcmar@redhat.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: linux-mips@linux-mips.org Cc: kvm@vger.kernel.org
* KVM: MIPS/Emulate: Update CP0_Compare emulation for VZJames Hogan2017-03-281-1/+42
| | | | | | | | | | | | | | | | | | | | | | | Update emulation of guest writes to CP0_Compare for VZ. There are two main differences compared to trap & emulate: - Writing to CP0_Compare in the VZ hardware guest context acks any pending timer, clearing CP0_Cause.TI. If we don't want an ack to take place we must carefully restore the TI bit if it was previously set. - Even with guest timer access disabled in CP0_GuestCtl0.GT, if the guest CP0_Count reaches the guest CP0_Compare the timer interrupt will assert. To prevent this we must set CP0_GTOffset to move the guest CP0_Count out of the way of the new guest CP0_Compare, either before or after depending on whether it is a forwards or backwards change. Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: "Radim Krčmář" <rkrcmar@redhat.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: linux-mips@linux-mips.org Cc: kvm@vger.kernel.org
* KVM: MIPS/TLB: Add VZ TLB managementJames Hogan2017-03-281-0/+404
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Add functions for MIPS VZ TLB management to tlb.c. kvm_vz_host_tlb_inv() will be used for invalidating root TLB entries after GPA page tables have been modified due to a KVM page fault. It arranges for a root GPA mapping to be flushed from the TLB, using the gpa_mm ASID or the current GuestID to do the probe. kvm_vz_local_flush_roottlb_all_guests() and kvm_vz_local_flush_guesttlb_all() flush all TLB entries in the corresponding TLB for guest mappings (GPA->RPA for root TLB with GuestID, and all entries for guest TLB). They will be used when starting a new GuestID cycle, when VZ hardware is enabled/disabled, and also when switching to a guest when the guest TLB contents may be stale or belong to a different VM. kvm_vz_guest_tlb_lookup() converts a guest virtual address to a guest physical address using the guest TLB. This will be used to decode guest virtual addresses which are sometimes provided by VZ hardware in CP0_BadVAddr for certain exceptions when the guest physical address is unavailable. kvm_vz_save_guesttlb() and kvm_vz_load_guesttlb() will be used to preserve wired guest VTLB entries while a guest isn't running. Signed-off-by: James Hogan <james.hogan@imgtec.com> Acked-by: Ralf Baechle <ralf@linux-mips.org> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: "Radim Krčmář" <rkrcmar@redhat.com> Cc: linux-mips@linux-mips.org Cc: kvm@vger.kernel.org
* KVM: MIPS/Entry: Update entry code to support VZJames Hogan2017-03-282-10/+126
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Update MIPS KVM entry code to support VZ: - We need to set GuestCtl0.GM while in guest mode. - For cores supporting GuestID, we need to set the root GuestID to match the main GuestID while in guest mode so that the root TLB refill handler writes the correct GuestID into the TLB. - For cores without GuestID where the root ASID dealiases RVA/GPA mappings, we need to load that ASID from the gpa_mm rather than the per-VCPU guest_kernel_mm or guest_user_mm, since the root TLB maps guest physical addresses. We also need to restore the normal process ASID on exit. - The normal linux process pgd needs restoring on exit, as we can't leave the GPA mappings active for kernel code. - GuestCtl0 needs saving on exit for the GExcCode field, as it may be clobbered if a preemption occurs. We also need to move the TLB refill handler to the XTLB vector at offset 0x80 on 64-bit VZ kernels, as hardware will use Root.Status.KX to determine whether a TLB refill or XTLB Refill exception is to be taken on a root TLB miss from guest mode, and KX needs to be set for kernel code to be able to access the 64-bit segments. Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: "Radim Krčmář" <rkrcmar@redhat.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: linux-mips@linux-mips.org Cc: kvm@vger.kernel.org
* KVM: MIPS: Abstract guest CP0 register access for VZJames Hogan2017-03-283-7/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Abstract the MIPS KVM guest CP0 register access macros into inline functions which are generated by macros. This allows them to be generated differently for VZ, where they will usually need to access the hardware guest CP0 context rather than the saved values in RAM. Accessors for each individual register are generated using these macros: - __BUILD_KVM_*_SW() for registers which are not present in the VZ hardware guest context, so kvm_{read,write}_c0_guest_##name() will access the saved value in RAM regardless of whether VZ is enabled. - __BUILD_KVM_*_HW() for registers which are present in the VZ hardware guest context, so kvm_{read,write}_c0_guest_##name() will access the hardware register when VZ is enabled. These build the underlying accessors using further macros: - __BUILD_KVM_*_SAVED() builds e.g. kvm_{read,write}_sw_gc0_##name() functions for accessing the saved versions of the registers in RAM. This is used for implementing the common kvm_{read,write}_c0_guest_##name() accessors with T&E where registers are always stored in RAM, but are also available with VZ HW registers to allow them to be accessed while saved. - __BUILD_KVM_*_VZ() builds e.g. kvm_{read,write}_vz_gc0_##name() functions for accessing the VZ hardware guest context registers directly. This is used for implementing the common kvm_{read,write}_c0_guest_##name() accessors with VZ. - __BUILD_KVM_*_WRAP() builds wrappers with different names, which allows the common kvm_{read,write}_c0_guest_##name() functions to be implemented using the VZ accessors while still having the SAVED accessors available too. - __BUILD_KVM_SAVE_VZ() builds functions for saving and restoring VZ hardware guest context register state to RAM, improving conciseness of VZ context saving and restoring. Similar macros exist for generating modifiers (set, clear, change), either with a normal unlocked read/modify/write, or using atomic LL/SC sequences. These changes change the types of 32-bit registers to u32 instead of unsigned long, which requires some changes to printk() functions in MIPS KVM. Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: "Radim Krčmář" <rkrcmar@redhat.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: linux-mips@linux-mips.org Cc: kvm@vger.kernel.org
* KVM: MIPS: Add guest exit exception callbackJames Hogan2017-03-283-0/+31
| | | | | | | | | | | | | | | | Add a callback for MIPS KVM implementations to handle the VZ guest exit exception. Currently the trap & emulate implementation contains a stub which reports an internal error, but the callback will be used properly by the VZ implementation. Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: "Radim Krčmář" <rkrcmar@redhat.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: linux-mips@linux-mips.org Cc: kvm@vger.kernel.org
* KVM: MIPS: Add hardware_{enable,disable} callbackJames Hogan2017-03-282-1/+17
| | | | | | | | | | | | | | Add an implementation callback for the kvm_arch_hardware_enable() and kvm_arch_hardware_disable() architecture functions, with simple stubs for trap & emulate. This is in preparation for VZ which will make use of them. Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: "Radim Krčmář" <rkrcmar@redhat.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: linux-mips@linux-mips.org Cc: kvm@vger.kernel.org
* KVM: MIPS: Add callback to check extensionJames Hogan2017-03-282-2/+18
| | | | | | | | | | | | | Add an implementation callback for checking presence of KVM extensions. This allows implementation specific extensions to be provided without ifdefs in mips.c. Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: "Radim Krčmář" <rkrcmar@redhat.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: linux-mips@linux-mips.org Cc: kvm@vger.kernel.org
* KVM: MIPS: Init timer frequency from callbackJames Hogan2017-03-283-10/+9
| | | | | | | | | | | | | | | | | | Currently the software emulated timer is initialised to a frequency of 100MHz by kvm_mips_init_count(), but this isn't suitable for VZ where the frequency of the guest timer matches that of the host. Add a count_hz argument so the caller can specify the default frequency, and move the call from kvm_arch_vcpu_create() to the implementation specific vcpu_setup() callback, so that VZ can specify a different frequency. Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: "Radim Krčmář" <rkrcmar@redhat.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: linux-mips@linux-mips.org Cc: kvm@vger.kernel.org
* KVM: MIPS: Add VZ & TE capabilitiesJames Hogan2017-03-281-0/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Add new KVM_CAP_MIPS_VZ and KVM_CAP_MIPS_TE capabilities, and in order to allow MIPS KVM to support VZ without confusing old users (which expect the trap & emulate implementation), define and start checking KVM_CREATE_VM type codes. The codes available are: - KVM_VM_MIPS_TE = 0 This is the current value expected from the user, and will create a VM using trap & emulate in user mode, confined to the user mode address space. This may in future become unavailable if the kernel is only configured to support VZ, in which case the EINVAL error will be returned and KVM_CAP_MIPS_TE won't be available even though KVM_CAP_MIPS_VZ is. - KVM_VM_MIPS_VZ = 1 This can be provided when the KVM_CAP_MIPS_VZ capability is available to create a VM using VZ, with a fully virtualized guest virtual address space. If VZ support is unavailable in the kernel, the EINVAL error will be returned (although old kernels without the KVM_CAP_MIPS_VZ capability may well succeed and create a trap & emulate VM). This is designed to allow the desired implementation (T&E vs VZ) to be potentially chosen at runtime rather than being fixed in the kernel configuration. Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: "Radim Krčmář" <rkrcmar@redhat.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: linux-mips@linux-mips.org Cc: kvm@vger.kernel.org Cc: linux-doc@vger.kernel.org
* KVM: MIPS: Extend counters & events for VZ GExcCodesJames Hogan2017-03-282-1/+27
| | | | | | | | | | | | | | | Extend MIPS KVM stats counters and kvm_transition trace event codes to cover hypervisor exceptions, which have their own GExcCode field in CP0_GuestCtl0 with up to 32 hypervisor exception cause codes. Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: "Radim Krčmář" <rkrcmar@redhat.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: linux-mips@linux-mips.org Cc: kvm@vger.kernel.org
* KVM: MIPS: Update kvm_lose_fpu() for VZJames Hogan2017-03-281-8/+12
| | | | | | | | | | | | | | | | | | | | | | | Update the implementation of kvm_lose_fpu() for VZ, where there is no need to enable the FPU/MSA in the root context if the FPU/MSA state is loaded but disabled in the guest context. The trap & emulate implementation needs to disable FPU/MSA in the root context when the guest disables them in order to catch the COP1 unusable or MSA disabled exception when they're used and pass it on to the guest. For VZ however as long as the context is loaded and enabled in the root context, the guest can enable and disable it in the guest context without the hypervisor having to do much, and will take guest exceptions without hypervisor intervention if used without being enabled in the guest context. Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: "Radim Krčmář" <rkrcmar@redhat.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: linux-mips@linux-mips.org Cc: kvm@vger.kernel.org
* KVM: MIPS/Emulate: Implement 64-bit MMIO emulationJames Hogan2017-03-281-1/+28
| | | | | | | | | | | | | Implement additional MMIO emulation for MIPS64, including 64-bit loads/stores, and 32-bit unsigned loads. These are only exposed on 64-bit VZ hosts. Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: "Radim Krčmář" <rkrcmar@redhat.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: linux-mips@linux-mips.org Cc: kvm@vger.kernel.org
* KVM: MIPS/Emulate: De-duplicate MMIO emulationJames Hogan2017-03-281-156/+50
| | | | | | | | | | | | | | | | | | | Refactor MIPS KVM MMIO load/store emulation to reduce code duplication. Each duplicate differed slightly anyway, and it will simplify adding 64-bit MMIO support for VZ. kvm_mips_emulate_store() and kvm_mips_emulate_load() can now return EMULATE_DO_MMIO (as possibly originally intended). We therefore stop calling either of these from kvm_mips_emulate_inst(), which is now only used by kvm_trap_emul_handle_cop_unusable() which is picky about return values. Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: "Radim Krčmář" <rkrcmar@redhat.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: linux-mips@linux-mips.org Cc: kvm@vger.kernel.org
* KVM: MIPS: Implement HYPCALL emulationJames Hogan2017-03-284-0/+61
| | | | | | | | | | | | | | | | | | | | | | | Emulate the HYPCALL instruction added in the VZ ASE and used by the MIPS paravirtualised guest support that is already merged. The new hypcall.c handles arguments and the return value. No actual hypercalls are yet supported, but this still allows us to safely step over hypercalls and set an error code in the return value for forward compatibility. Non-zero HYPCALL codes are not handled. We also document the hypercall ABI which asm/kvm_para.h uses. Signed-off-by: James Hogan <james.hogan@imgtec.com> Acked-by: Ralf Baechle <ralf@linux-mips.org> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: "Radim Krčmář" <rkrcmar@redhat.com> Cc: Andreas Herrmann <andreas.herrmann@caviumnetworks.com> Cc: David Daney <david.daney@cavium.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: linux-mips@linux-mips.org Cc: kvm@vger.kernel.org Cc: linux-doc@vger.kernel.org
* sched/headers: Prepare to move signal wakeup & sigpending methods from ↵Ingo Molnar2017-03-021-0/+2
| | | | | | | | | | | | | <linux/sched.h> into <linux/sched/signal.h> Fix up affected files that include this signal functionality via sched.h. Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* KVM: race-free exit from KVM_RUN without POSIX signalsPaolo Bonzini2017-02-171-1/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The purpose of the KVM_SET_SIGNAL_MASK API is to let userspace "kick" a VCPU out of KVM_RUN through a POSIX signal. A signal is attached to a dummy signal handler; by blocking the signal outside KVM_RUN and unblocking it inside, this possible race is closed: VCPU thread service thread -------------------------------------------------------------- check flag set flag raise signal (signal handler does nothing) KVM_RUN However, one issue with KVM_SET_SIGNAL_MASK is that it has to take tsk->sighand->siglock on every KVM_RUN. This lock is often on a remote NUMA node, because it is on the node of a thread's creator. Taking this lock can be very expensive if there are many userspace exits (as is the case for SMP Windows VMs without Hyper-V reference time counter). As an alternative, we can put the flag directly in kvm_run so that KVM can see it: VCPU thread service thread -------------------------------------------------------------- raise signal signal handler set run->immediate_exit KVM_RUN check run->immediate_exit Reviewed-by: Radim Krčmář <rkrcmar@redhat.com> Reviewed-by: David Hildenbrand <david@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* KVM: MIPS: Allow multiple VCPUs to be createdJames Hogan2017-02-031-0/+6
| | | | | | | | | | | | | | | | | | Increase the maximum number of MIPS KVM VCPUs to 8, and implement the KVM_CAP_NR_VCPUS and KVM_CAP_MAX_CPUS capabilities which expose the recommended and maximum number of VCPUs to userland. The previous maximum of 1 didn't allow for any form of SMP guests. We calculate the values similarly to ARM, recommending as many VCPUs as there are CPUs online in the system. This will allow userland to know how many VCPUs it is possible to create. Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: "Radim Krčmář" <rkrcmar@redhat.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: linux-mips@linux-mips.org Cc: kvm@vger.kernel.org
* KVM: MIPS/T&E: Expose read-only CP0_IntCtl registerJames Hogan2017-02-031-0/+7
| | | | | | | | | | | | | | | | | Expose the CP0_IntCtl register through the KVM register access API, which is a required register since MIPS32r2. It is currently read-only since the VS field isn't implemented due to lack of Config3.VInt or Config3.VEIC. It is implemented in trap_emul.c so that a VZ implementation can allow writes. Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: "Radim Krčmář" <rkrcmar@redhat.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: linux-mips@linux-mips.org Cc: kvm@vger.kernel.org
* KVM: MIPS/T&E: Expose CP0_EntryLo0/1 registersJames Hogan2017-02-031-0/+14
| | | | | | | | | | | | | | | | | | Expose the CP0_EntryLo0 and CP0_EntryLo1 registers through the KVM register access API. This is fairly straightforward for trap & emulate since we don't support the RI and XI bits. For the sake of future proofing (particularly for VZ) it is explicitly specified that the API always exposes the 64-bit version of these registers (i.e. with the RI and XI bits in bit positions 63 and 62 respectively), and they are implemented in trap_emul.c rather than mips.c to allow them to be implemented differently for VZ. Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: "Radim Krčmář" <rkrcmar@redhat.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: linux-mips@linux-mips.org Cc: kvm@vger.kernel.org
* KVM: MIPS/T&E: Default to reset vectorJames Hogan2017-02-031-0/+6
| | | | | | | | | | | | | | | | | | Set the default VCPU state closer to the architectural reset state, with PC pointing at the reset vector (uncached PA 0x1fc00000, which for KVM T&E is VA 0x5fc00000), and with CP0_Status.BEV and CP0_Status.ERL to 1. Although QEMU at least will overwrite this state, it makes sense to do this now that CP0_EBase is properly implemented to check BEV, and now that we support a sparse GPA layout potentially with a boot ROM at GPA 0x1fc00000. Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: "Radim Krčmář" <rkrcmar@redhat.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: linux-mips@linux-mips.org Cc: kvm@vger.kernel.org
* KVM: MIPS/T&E: Implement CP0_EBase registerJames Hogan2017-02-033-33/+57
| | | | | | | | | | | | | | | | | | | | | | The CP0_EBase register is a standard feature of MIPS32r2, so we should always have been implementing it properly. However the register value was ignored and wasn't exposed to userland. Fix the emulation of exceptions and interrupts to use the value stored in guest CP0_EBase, and fix the masks so that the top 3 bits (rather than the standard 2) are fixed, so that it is always in the guest KSeg0 segment. Also add CP0_EBASE to the KVM one_reg interface so it can be accessed by userland, also allowing the CPU number field to be written (which isn't permitted by the guest). Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: "Radim Krčmář" <rkrcmar@redhat.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: linux-mips@linux-mips.org Cc: kvm@vger.kernel.org
* KVM: MIPS/T&E: Move CP0 register access into T&EJames Hogan2017-02-033-202/+179
| | | | | | | | | | | | | | Access to various CP0 registers via the KVM register access API needs to be implementation specific to allow restrictions to be made on changes, for example when VZ guest registers aren't present, so move them all into trap_emul.c in preparation for VZ. Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: "Radim Krčmář" <rkrcmar@redhat.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: linux-mips@linux-mips.org Cc: kvm@vger.kernel.org
* KVM: MIPS: Claim KVM_CAP_READONLY_MEM supportJames Hogan2017-02-031-0/+1
| | | | | | | | | | | | | Now that load/store faults due to read only memory regions are treated as MMIO accesses it is safe to claim support for read only memory regions (KVM_CAP_READONLY_MEM). Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: "Radim Krčmář" <rkrcmar@redhat.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: linux-mips@linux-mips.org Cc: kvm@vger.kernel.org
* KVM: MIPS/MMU: Implement KVM_CAP_SYNC_MMUJames Hogan2017-02-033-17/+220
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Implement the SYNC_MMU capability for KVM MIPS, allowing changes in the underlying user host virtual address (HVA) mappings to be promptly reflected in the corresponding guest physical address (GPA) mappings. This allows for several features to work with guest RAM which require mappings to be altered or protected, such as copy-on-write, KSM (Kernel Samepage Merging), idle page tracking, memory swapping, and guest memory ballooning. There are two main aspects of this change, described below. The KVM MMU notifier architecture callbacks are implemented so we can be notified of changes in the HVA mappings. These arrange for the guest physical address (GPA) page tables to be modified and possibly for derived mappings (GVA page tables and TLBs) to be flushed. - kvm_unmap_hva[_range]() - These deal with HVA mappings being removed, for example before a copy-on-write takes place, which requires the corresponding GPA page table mappings to be removed too. - kvm_set_spte_hva() - These update a GPA page table entry to match the new HVA entry, but must be careful to respect KVM specific configuration such as not dirtying a clean guest page which is dirty to the host, and write protecting writable pages in read only memslots (which will soon be supported). - kvm[_test]_age_hva() - These update GPA page table entries to be old (invalid) so that access can be tracked, making them young again. The GPA page fault handling (kvm_mips_map_page) is updated to use gfn_to_pfn_prot() (which may provide read-only pages), to handle asynchronous page table invalidation from MMU notifier callbacks, and to handle more cases in the fast path. - mmu_notifier_seq is used to detect asynchronous page table invalidations while we're holding a pfn from gfn_to_pfn_prot() outside of kvm->mmu_lock, retrying if invalidations have taken place, e.g. a COW or a KSM page merge. - The fast path (_kvm_mips_map_page_fast) now handles marking old pages as young / accessed, and disallowing dirtying of clean pages that aren't actually writable (e.g. shared pages that should COW, and read-only memory regions when they are enabled in a future patch). - Due to the use of MMU notifications we no longer need to keep the page references after we've updated the GPA page tables. Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: "Radim Krčmář" <rkrcmar@redhat.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: linux-mips@linux-mips.org Cc: kvm@vger.kernel.org
* KVM: MIPS/MMU: Pass GPA PTE bits to mapped GVA PTEsJames Hogan2017-02-031-19/+37
| | | | | | | | | | | | | | | | | | | | | Propagate the GPA PTE protection bits on to the GVA PTEs on a mapped fault (except _PAGE_WRITE, and filtered by the guest TLB entry), rather than always overriding the protection. This allows dirty page tracking to work in mapped guest segments as a clear dirty bit in the GPA PTE will propagate to the GVA PTEs even when the guest TLB has the dirty bit set. Since the filtering of protection bits is now abstracted, if the buddy GVA PTE is also valid, we obtain the corresponding GPA PTE using a simple non-allocating walk and load that into the GVA PTE similarly (which may itself be invalid). Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: "Radim Krčmář" <rkrcmar@redhat.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: linux-mips@linux-mips.org Cc: kvm@vger.kernel.org
* KVM: MIPS/MMU: Pass GPA PTE bits to KSeg0 GVA PTEsJames Hogan2017-02-031-23/+26
| | | | | | | | | | | | | | | | | | | Propagate the GPA PTE protection bits on to the GVA PTEs on a KSeg0 fault (except _PAGE_WRITE), rather than always overriding the protection. This allows dirty page tracking to work in KSeg0 as a clear dirty bit in the GPA PTE will propagate to the GVA PTEs. This makes it simpler to use a single kvm_mips_map_page() to obtain both the main GPA PTE and its buddy (which may be invalid), which also allows memory regions to be fully accessible when they don't start and end on a 2*PAGE_SIZE boundary. Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: "Radim Krčmář" <rkrcmar@redhat.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: linux-mips@linux-mips.org Cc: kvm@vger.kernel.org
* KVM: MIPS/MMU: Handle dirty logging on GPA faultsJames Hogan2017-02-031-4/+70
| | | | | | | | | | | | | | | | | | | | | Update kvm_mips_map_page() to handle logging of dirty guest physical pages. Upcoming patches will propagate the dirty bit to the GVA page tables. A fast path is added for handling protection bits that can be resolved without calling into KVM, currently just dirtying of clean pages being written to. The slow path marks the GPA page table entry writable only on writes, and at the same time marks the page dirty in the dirty page logging bitmask. Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: "Radim Krčmář" <rkrcmar@redhat.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: linux-mips@linux-mips.org Cc: kvm@vger.kernel.org
* KVM: MIPS: Clean & flush on dirty page logging enableJames Hogan2017-02-031-0/+24
| | | | | | | | | | | | | | When an existing memory region has dirty page logging enabled, make the entire slot clean (read only) so that writes will immediately start logging dirty pages (once the dirty bit is transferred from GPA to GVA page tables in an upcoming patch). Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: "Radim Krčmář" <rkrcmar@redhat.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: linux-mips@linux-mips.org Cc: kvm@vger.kernel.org
* KVM: MIPS/MMU: Use generic dirty log & protect helperJames Hogan2017-02-033-19/+46
| | | | | | | | | | | | | | | | | | | | | | | | MIPS hasn't up to this point properly supported dirty page logging, as pages in slots with dirty logging enabled aren't made clean, and tlbmod exceptions from writes to clean pages have been assumed to be due to guest TLB protection and unconditionally passed to the guest. Use the generic dirty logging helper kvm_get_dirty_log_protect() to properly implement kvm_vm_ioctl_get_dirty_log(), similar to how ARM does. This uses xchg to clear the dirty bits when reading them, rather than wiping them out afterwards with a memset, which would potentially wipe recently set bits that weren't caught by kvm_get_dirty_log(). It also makes the pages clean again using the kvm_arch_mmu_enable_log_dirty_pt_masked() architecture callback so that further writes after the shadow memslot is flushed will trigger tlbmod exceptions and dirty handling. Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: "Radim Krčmář" <rkrcmar@redhat.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: linux-mips@linux-mips.org Cc: kvm@vger.kernel.org
* KVM: MIPS/MMU: Add GPA PT mkclean helperJames Hogan2017-02-031-0/+124
| | | | | | | | | | | | | | | | | Add a helper function to make a range of guest physical address (GPA) mappings in the GPA page table clean so that writes can be caught. This will be used in a few places to manage dirty page logging. Note that until the dirty bit is transferred from GPA page table entries to GVA page table entries in an upcoming patch this won't trigger a TLB modified exception on write. Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: "Radim Krčmář" <rkrcmar@redhat.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: linux-mips@linux-mips.org Cc: kvm@vger.kernel.org
* KVM: MIPS/T&E: Handle read only GPA in TLB modJames Hogan2017-02-032-57/+43
| | | | | | | | | | | | | | | | | | | | | | | Rewrite TLB modified exception handling to handle read only GPA memory regions, instead of unconditionally passing the exception to the guest. If the guest TLB is not the cause of the exception we call into the normal TLB fault handling depending on the memory segment, which will soon attempt to remap the physical page to be writable (handling dirty page tracking or copy on write in the process). Failing that we fall back to treating it as MMIO, due to a read only memory region. Once the capability is enabled, this will allow read only memory regions (such as the Malta boot flash as emulated by QEMU) to have writes treated as MMIO, while still allowing reads to run untrapped. Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: "Radim Krčmář" <rkrcmar@redhat.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: linux-mips@linux-mips.org Cc: kvm@vger.kernel.org
* KVM: MIPS/T&E: Treat unhandled guest KSeg0 as MMIOJames Hogan2017-02-032-6/+5
| | | | | | | | | | | | | | | | | | Treat unhandled accesses to guest KSeg0 as MMIO, rather than only host KSeg0 addresses. This will allow read only memory regions (such as the Malta boot flash as emulated by QEMU) to have writes (before reads) treated as MMIO, and unallocated physical addresses to have all accesses treated as MMIO. The MMIO emulation uses the gva_to_gpa callback, so this is also updated for trap & emulate to handle guest KSeg0 addresses. Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: "Radim Krčmář" <rkrcmar@redhat.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: linux-mips@linux-mips.org Cc: kvm@vger.kernel.org
* KVM: MIPS/T&E: Abstract bad access handlingJames Hogan2017-02-031-47/+72
| | | | | | | | | | | | | | | | | | Abstract the handling of bad guest loads and stores which may need to trigger an MMIO, so that the same code can be used in a later patch for guest KSeg0 addresses (TLB exception handling) as well as for host KSeg1 addresses (existing address error exception and TLB exception handling). We now use kvm_mips_emulate_store() and kvm_mips_emulate_load() directly rather than the more generic kvm_mips_emulate_inst(), as there is no need to expose emulation of any other instructions. Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: "Radim Krčmář" <rkrcmar@redhat.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: linux-mips@linux-mips.org Cc: kvm@vger.kernel.org
* KVM: MIPS: Pass type of fault down to kvm_mips_map_page()James Hogan2017-02-033-13/+19
| | | | | | | | | | | | | | | kvm_mips_map_page() will need to know whether the fault was due to a read or a write in order to support dirty page tracking, KVM_CAP_SYNC_MMU, and read only memory regions, so get that information passed down to it via new bool write_fault arguments to various functions. Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: "Radim Krčmář" <rkrcmar@redhat.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: linux-mips@linux-mips.org Cc: kvm@vger.kernel.org
* KVM: MIPS/T&E: Ignore user writes to CP0_Config7James Hogan2017-02-031-0/+3
| | | | | | | | | | | | | | | | | Ignore userland writes to CP0_Config7 rather than reporting an error, since we do allow reads of this register and it is claimed to exist in the ioctl API. This allows userland to blindly save and restore KVM registers without having to special case certain registers as not being writable, for example during live migration once dirty page logging is fixed. Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: "Radim Krčmář" <rkrcmar@redhat.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: linux-mips@linux-mips.org Cc: kvm@vger.kernel.org
* KVM: MIPS: Implement kvm_arch_flush_shadow_all/memslotJames Hogan2017-02-032-0/+40
| | | | | | | | | | | | | | | | | | | | | | | | | | | Implement the kvm_arch_flush_shadow_all() and kvm_arch_flush_shadow_memslot() KVM functions for MIPS to allow guest physical mappings to be safely changed. The general MIPS KVM code takes care of flushing of GPA page table entries. kvm_arch_flush_shadow_all() flushes the whole GPA page table, and is always called on the cleanup path so there is no need to acquire the kvm->mmu_lock. kvm_arch_flush_shadow_memslot() flushes only the range of mappings in the GPA page table corresponding to the slot being flushed, and happens when memory regions are moved or deleted. MIPS KVM implementation callbacks are added for handling the implementation specific flushing of mappings derived from the GPA page tables. These are implemented for trap_emul.c using kvm_flush_remote_tlbs() which should now be functional, and will flush the per-VCPU GVA page tables and ASIDS synchronously (before next entering guest mode or directly accessing GVA space). Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: "Radim Krčmář" <rkrcmar@redhat.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: linux-mips@linux-mips.org Cc: kvm@vger.kernel.org
* KVM: MIPS/Emulate: Use lockless GVA helpers for cache emulationJames Hogan2017-02-032-118/+65
| | | | | | | | | | | | | | | | | | | | | | | | | | | Use the lockless GVA helpers to implement the reading of guest instructions for emulation. This will allow it to handle asynchronous TLB flushes when they are implemented. This is a little more complicated than the other two cases (get_inst() and dynamic translation) due to the need to emulate the appropriate guest TLB exception when the address isn't present or isn't valid in the guest TLB. Since there are several protected cache ops that may need to be performed safely, this is abstracted by kvm_mips_guest_cache_op() which is passed a protected cache op function pointer and takes care of the lockless operation and fault handling / retry if the op should fail, taking advantage of the new errors which the protected cache ops can now return. This allows the existing advance fault handling which relied on host TLB lookups to be removed, along with the now unused kvm_mips_host_tlb_lookup(), Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: "Radim Krčmář" <rkrcmar@redhat.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: linux-mips@linux-mips.org Cc: kvm@vger.kernel.org
* KVM: MIPS/MMU: Use lockless GVA helpers for get_inst()James Hogan2017-02-031-3/+18
| | | | | | | | | | | | | Use the lockless GVA helpers to implement the reading of guest instructions for emulation. This will allow it to handle asynchronous TLB flushes when they are implemented. Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: "Radim Krčmář" <rkrcmar@redhat.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: linux-mips@linux-mips.org Cc: kvm@vger.kernel.org
* KVM: MIPS/T&E: Use lockless GVA helpers for dyntransJames Hogan2017-02-031-2/+24
| | | | | | | | | | | | | Use the lockless GVA helpers to implement the dynamic translation of guest instructions. This will allow it to handle asynchronous TLB flushes when they are implemented. Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: "Radim Krčmář" <rkrcmar@redhat.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: linux-mips@linux-mips.org Cc: kvm@vger.kernel.org
* KVM: MIPS/T&E: Add lockless GVA access helpersJames Hogan2017-02-032-0/+116
| | | | | | | | | | | | | | | | | | | | | Add helpers to allow for lockless direct access to the GVA space, by changing the VCPU mode to READING_SHADOW_PAGE_TABLES for the duration of the access. This allows asynchronous TLB flush requests in future patches to safely trigger either a TLB flush before the direct GVA space access, or a delay until the in-progress lockless direct access is complete. The kvm_trap_emul_gva_lockless_begin() and kvm_trap_emul_gva_lockless_end() helpers take care of guarding the direct GVA accesses, and kvm_trap_emul_gva_fault() tries to handle a uaccess fault resulting from a flush having taken place. Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: "Radim Krčmář" <rkrcmar@redhat.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: linux-mips@linux-mips.org Cc: kvm@vger.kernel.org
* KVM: MIPS/T&E: Reduce stale ASID checksJames Hogan2017-02-031-29/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | The stale ASID checks taking place on VCPU load can be reduced: - Now that we check for a stale ASID on guest re-entry, there is no need to do so when loading the VCPU outside of guest context, since it will happen before entering the guest. Note that a lot of KVM VCPU ioctls will cause the VCPU to be loaded but guest context won't be entered. - There is no need to check for a stale kernel_mm ASID when the guest is in user mode and vice versa. In fact doing so can potentially be problematic since the user_mm ASID regeneration may trigger a new ASID cycle, which would cause the kern_mm ASID to become stale after it has been checked for staleness. Therefore only check the ASID for the mm corresponding to the current guest mode, and only if we're already in guest context. We drop some of the related kvm_debug() calls here too. Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: "Radim Krčmář" <rkrcmar@redhat.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: linux-mips@linux-mips.org Cc: kvm@vger.kernel.org
* KVM: MIPS/T&E: Handle TLB invalidation requestsJames Hogan2017-02-031-8/+63
| | | | | | | | | | | | | | | | | | | | | | | Add handling of TLB invalidation requests before entering guest mode. This will allow asynchonous invalidation of the VCPU mappings when physical memory regions are altered. Should the CPU running the VCPU already be in guest mode an IPI will be sent to trigger a guest exit. The reload_asid path will be used in a future patch for when GVA is about to be directly accessed by KVM. In the process, the stale user ASID check in the re-entry path (for lazy user GVA flushing) is generalised to check the ASID for the current guest mode, in case a TLB invalidation request was handled. This has the side effect of making the ASID checks on vcpu_load too conservative, which will be addressed in a later patch. Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: "Radim Krčmář" <rkrcmar@redhat.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: linux-mips@linux-mips.org Cc: kvm@vger.kernel.org
* KVM: MIPS: Update vcpu->mode and vcpu->cpuJames Hogan2017-02-032-0/+20
| | | | | | | | | | | | | | | | | | | | | | | Keep the vcpu->mode and vcpu->cpu variables up to date so that kvm_make_all_cpus_request() has a chance of functioning correctly. This will soon need to be used for kvm_flush_remote_tlbs(). We can easily update vcpu->cpu when the VCPU context is loaded or saved, which will happen when accessing guest context and when the guest is scheduled in and out. We need to be a little careful with vcpu->mode though, as we will in future be checking for outstanding VCPU requests, and this must be done after the value of IN_GUEST_MODE in vcpu->mode is visible to other CPUs. Otherwise the other CPU could fail to trigger an IPI to wait for completion dispite the VCPU request not being seen. Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: "Radim Krčmář" <rkrcmar@redhat.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: linux-mips@linux-mips.org Cc: kvm@vger.kernel.org
* KVM: MIPS/MMU: Convert guest physical map to page tableJames Hogan2017-02-032-67/+274
| | | | | | | | | | | | | | | | | | | | | | | | | | | Current guest physical memory is mapped to host physical addresses using a single linear array (guest_pmap of length guest_pmap_npages). This was only really meant to be temporary, and isn't sparse, so its wasteful of memory. A small amount of RAM at GPA 0 and a small boot exception vector at GPA 0x1fc00000 cannot be represented without a full 128KiB guest_pmap allocation (MIPS32 with 16KiB pages), which is one reason why QEMU currently runs its boot code at the top of RAM instead of the usual boot exception vector address. Instead use the existing infrastructure for host virtual page table management to allocate a page table for guest physical memory too. This should be sufficient for now, assuming the size of physical memory doesn't exceed the size of virtual memory. It may need extending in future to handle XPA (eXtended Physical Addressing) in 32-bit guests, as supported by VZ guests on P5600. Some of this code is based loosely on Cavium's VZ KVM implementation. Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: "Radim Krčmář" <rkrcmar@redhat.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: linux-mips@linux-mips.org Cc: kvm@vger.kernel.org
* KVM: MIPS: Use CP0_BadInstr[P] for emulationJames Hogan2017-02-033-4/+60
| | | | | | | | | | | | | | | | | | | | | | | | | When exiting from the guest, store the values of the CP0_BadInstr and CP0_BadInstrP registers if they exist, which contain the encodings of the instructions which caused the last synchronous exception. When the instruction is needed for emulation, kvm_get_badinstr() and kvm_get_badinstrp() are used instead of calling kvm_get_inst() directly, to decide whether to read the saved CP0_BadInstr/CP0_BadInstrP registers (if they exist), or read the instruction from memory (if not). The use of these registers should be more robust than using kvm_get_inst(), as it actually gives the instruction encoding seen by the hardware rather than relying on user accessors after the fact, which can be fooled by incoherent icache or a racing code modification. It will also work with VZ, where the guest virtual memory isn't directly accessible by the host with user accessors. Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: "Radim Krčmář" <rkrcmar@redhat.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: linux-mips@linux-mips.org Cc: kvm@vger.kernel.org
* KVM: MIPS: Improve kvm_get_inst() error returnJames Hogan2017-02-033-51/+55
| | | | | | | | | | | | | | | | | | Currently kvm_get_inst() returns KVM_INVALID_INST in the event of a fault reading the guest instruction. This has the rather arbitrary magic value 0xdeadbeef. This API isn't very robust, and in fact 0xdeadbeef is a valid MIPS64 instruction encoding, namely "ld t1,-16657(s5)". Therefore change the kvm_get_inst() API to return 0 or -EFAULT, and to return the instruction via a u32 *out argument. We can then drop the KVM_INVALID_INST definition entirely. Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: "Radim Krčmář" <rkrcmar@redhat.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: linux-mips@linux-mips.org Cc: kvm@vger.kernel.org
generated by cgit v1.2.3 (git 2.46.0) at 2025-04-24 18:51:04 +0000