- 02 Apr, 2022 17 commits
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Jim Mattson authored
AMD EPYC CPUs never raise a #GP for a WRMSR to a PerfEvtSeln MSR. Some reserved bits are cleared, and some are not. Specifically, on Zen3/Milan, bits 19 and 42 are not cleared. When emulating such a WRMSR, KVM should not synthesize a #GP, regardless of which bits are set. However, undocumented bits should not be passed through to the hardware MSR. So, rather than checking for reserved bits and synthesizing a #GP, just clear the reserved bits. This may seem pedantic, but since KVM currently does not support the "Host/Guest Only" bits (41:40), it is necessary to clear these bits rather than synthesizing #GP, because some popular guests (e.g Linux) will set the "Host Only" bit even on CPUs that don't support EFER.SVME, and they don't expect a #GP. For example, root@Ubuntu1804:~# perf stat -e r26 -a sleep 1 Performance counter stats for 'system wide': 0 r26 1.001070977 seconds time elapsed Feb 23 03:59:58 Ubuntu1804 kernel: [ 405.379957] unchecked MSR access error: WRMSR to 0xc0010200 (tried to write 0x0000020000130026) at rIP: 0xffffffff9b276a28 (native_write_msr+0x8/0x30) Feb 23 03:59:58 Ubuntu1804 kernel: [ 405.379958] Call Trace: Feb 23 03:59:58 Ubuntu1804 kernel: [ 405.379963] amd_pmu_disable_event+0x27/0x90 Fixes: ca724305 ("KVM: x86/vPMU: Implement AMD vPMU code for KVM") Reported-by:Lotus Fenn <lotusf@google.com> Signed-off-by:
Jim Mattson <jmattson@google.com> Reviewed-by:
Like Xu <likexu@tencent.com> Reviewed-by:
David Dunn <daviddunn@google.com> Message-Id: <20220226234131.2167175-1-jmattson@google.com> Signed-off-by:
Paolo Bonzini <pbonzini@redhat.com>
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Sean Christopherson authored
Trace all APICv inhibit changes instead of just those that result in APICv being (un)inhibited, and log the current state. Debugging why APICv isn't working is frustrating as it's hard to see why APICv is still inhibited, and logging only the first inhibition means unnecessary onion peeling. Opportunistically drop the export of the tracepoint, it is not and should not be used by vendor code due to the need to serialize toggling via apicv_update_lock. Note, using the common flow means kvm_apicv_init() switched from atomic to non-atomic bitwise operations. The VM is unreachable at init, so non-atomic is perfectly ok. Signed-off-by:
Sean Christopherson <seanjc@google.com> Message-Id: <20220311043517.17027-4-seanjc@google.com> Signed-off-by:
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Sean Christopherson authored
Add set/clear wrappers for toggling APICv inhibits to make the call sites more readable, and opportunistically rename the inner helpers to align with the new wrappers and to make them more readable as well. Invert the flag from "activate" to "set"; activate is painfully ambiguous as it's not obvious if the inhibit is being activated, or if APICv is being activated, in which case the inhibit is being deactivated. For the functions that take @set, swap the order of the inhibit reason and @set so that the call sites are visually similar to those that bounce through the wrapper. Signed-off-by:
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Sean Christopherson authored
Use an enum for the APICv inhibit reasons, there is no meaning behind their values and they most definitely are not "unsigned longs". Rename the various params to "reason" for consistency and clarity (inhibit may be confused as a command, i.e. inhibit APICv, instead of the reason that is getting toggled/checked). No functional change intended. Signed-off-by:
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Lai Jiangshan authored
There are two kinds of implicit supervisor access implicit supervisor access when CPL = 3 implicit supervisor access when CPL < 3 Current permission_fault() handles only the first kind for SMAP. But if the access is implicit when SMAP is on, data may not be read nor write from any user-mode address regardless the current CPL. So the second kind should be also supported. The first kind can be detect via CPL and access mode: if it is supervisor access and CPL = 3, it must be implicit supervisor access. But it is not possible to detect the second kind without extra information, so this patch adds an artificial PFERR_EXPLICIT_ACCESS into @access. This extra information also works for the first kind, so the logic is changed to use this information for both cases. The value of PFERR_EXPLICIT_ACCESS is deliberately chosen to be bit 48 which is in the most significant 16 bits of u64 and less likely to be forced to change due to future hardware uses it. This patch removes the call to ->get_cpl() for access mode is determined by @access. Not only does it reduce a function call, but also remove confusions when the permission is checked for nested TDP. The nested TDP shouldn't have SMAP checking nor even the L2's CPL have any bearing on it. The original code works just because it is always user walk for NPT and SMAP fault is not set for EPT in update_permission_bitmask. Signed-off-by:
Lai Jiangshan <jiangshan.ljs@antgroup.com> Message-Id: <20220311070346.45023-5-jiangshanlai@gmail.com> Signed-off-by:
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Lai Jiangshan authored
Comments above the variable says the bit is set when SMAP is overridden or the same meaning in update_permission_bitmask(): it is not subjected to SMAP restriction. Renaming it to reflect the negative implication and make the code better readability. Signed-off-by:
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Lai Jiangshan authored
The commit 09f037aa ("KVM: MMU: speedup update_permission_bitmask") refactored the code of update_permission_bitmask() and change the comments. It added a condition into a list to match the new code, so the number/order for conditions in the comments should be updated too. Signed-off-by:
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Lai Jiangshan authored
Change the type of access u32 to u64 for FNAME(walk_addr) and ->gva_to_gpa(). The kinds of accesses are usually combinations of UWX, and VMX/SVM's nested paging adds a new factor of access: is it an access for a guest page table or for a final guest physical address. And SMAP relies a factor for supervisor access: explicit or implicit. So @access in FNAME(walk_addr) and ->gva_to_gpa() is better to include all these information to do the walk. Although @access(u32) has enough bits to encode all the kinds, this patch extends it to u64: o Extra bits will be in the higher 32 bits, so that we can easily obtain the traditional access mode (UWX) by converting it to u32. o Reuse the value for the access kind defined by SVM's nested paging (PFERR_GUEST_FINAL_MASK and PFERR_GUEST_PAGE_MASK) as @error_code in kvm_handle_page_fault(). Signed-off-by:
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David Woodhouse authored
It isn't OK to cache the dirty status of a page in internal structures for an indefinite period of time. Any time a vCPU exits the run loop to userspace might be its last; the VMM might do its final check of the dirty log, flush the last remaining dirty pages to the destination and complete a live migration. If we have internal 'dirty' state which doesn't get flushed until the vCPU is finally destroyed on the source after migration is complete, then we have lost data because that will escape the final copy. This problem already exists with the use of kvm_vcpu_unmap() to mark pages dirty in e.g. VMX nesting. Note that the actual Linux MM already considers the page to be dirty since we have a writeable mapping of it. This is just about the KVM dirty logging. For the nesting-style use cases (KVM_GUEST_USES_PFN) we will need to track which gfn_to_pfn_caches have been used and explicitly mark the corresponding pages dirty before returning to userspace. But we would have needed external tracking of that anyway, rather than walking the full list of GPCs to find those belonging to this vCPU which are dirty. So let's rely *solely* on that external tracking, and keep it simple rather than laying a tempting trap for callers to fall into. Signed-off-by:
David Woodhouse <dwmw@amazon.co.uk> Signed-off-by:
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Sean Christopherson authored
Replace the guest_uses_pa and kernel_map booleans in the PFN cache code with a unified enum/bitmask. Using explicit names makes it easier to review and audit call sites. Opportunistically add a WARN to prevent passing garbage; instantating a cache without declaring its usage is either buggy or pointless. Signed-off-by:
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Peter Gonda authored
Include kvm_cache_regs.h to pick up the definition of is_guest_mode(), which is referenced by nested_svm_virtualize_tpr() in svm.h. Remove include from svm_onhpyerv.c which was done only because of lack of include in svm.h. Fixes: 883b0a91 ("KVM: SVM: Move Nested SVM Implementation to nested.c") Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Sean Christopherson <seanjc@google.com> Cc: kvm@vger.kernel.org Cc: linux-kernel@vger.kernel.org Signed-off-by:
Peter Gonda <pgonda@google.com> Message-Id: <20220304161032.2270688-1-pgonda@google.com> Signed-off-by:
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Jim Mattson authored
The third nybble of AMD's event select overlaps with Intel's IN_TX and IN_TXCP bits. Therefore, we can't use AMD64_RAW_EVENT_MASK on Intel platforms that support TSX. Declare a raw_event_mask in the kvm_pmu structure, initialize it in the vendor-specific pmu_refresh() functions, and use that mask for PERF_TYPE_RAW configurations in reprogram_gp_counter(). Fixes: 710c4765 ("KVM: x86/pmu: Use AMD64_RAW_EVENT_MASK for PERF_TYPE_RAW") Signed-off-by:
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Sean Christopherson authored
Don't actually set a request bit in vcpu->requests when making a request purely to force a vCPU to exit the guest. Logging a request but not actually consuming it would cause the vCPU to get stuck in an infinite loop during KVM_RUN because KVM would see the pending request and bail from VM-Enter to service the request. Note, it's currently impossible for KVM to set KVM_REQ_GPC_INVALIDATE as nothing in KVM is wired up to set guest_uses_pa=true. But, it'd be all too easy for arch code to introduce use of kvm_gfn_to_pfn_cache_init() without implementing handling of the request, especially since getting test coverage of MMU notifier interaction with specific KVM features usually requires a directed test. Opportunistically rename gfn_to_pfn_cache_invalidate_start()'s wake_vcpus to evict_vcpus. The purpose of the request is to get vCPUs out of guest mode, it's supposed to _avoid_ waking vCPUs that are blocking. Opportunistically rename KVM_REQ_GPC_INVALIDATE to be more specific as to what it wants to accomplish, and to genericize the name so that it can used for similar but unrelated scenarios, should they arise in the future. Add a comment and documentation to explain why the "no action" request exists. Add compile-time assertions to help detect improper usage. Use the inner assertless helper in the one s390 path that makes requests without a hardcoded request. Cc: David Woodhouse <dwmw@amazon.co.uk> Signed-off-by:
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David Woodhouse authored
If the cache's user host virtual address becomes invalid, there is still a path from kvm_gfn_to_pfn_cache_refresh() where __release_gpc() could release the pfn but the gpc->pfn field has not been overwritten with an error value. If this happens, kvm_gfn_to_pfn_cache_unmap will call put_page again on the same page. Cc: stable@vger.kernel.org Fixes: 982ed0de ("KVM: Reinstate gfn_to_pfn_cache with invalidation support") Signed-off-by:
David Woodhouse <dwmw2@infradead.org> Signed-off-by:
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Sean Christopherson authored
Re-introduce zapping only leaf SPTEs in kvm_zap_gfn_range() and kvm_tdp_mmu_unmap_gfn_range(), this time without losing a pending TLB flush when processing multiple roots (including nested TDP shadow roots). Dropping the TLB flush resulted in random crashes when running Hyper-V Server 2019 in a guest with KSM enabled in the host (or any source of mmu_notifier invalidations, KSM is just the easiest to force). This effectively revert commits 873dd122 and fcb93eb6, and thus restores commit cf3e2642, plus this delta on top: bool kvm_tdp_mmu_zap_leafs(struct kvm *kvm, int as_id, gfn_t start, gfn_t end, struct kvm_mmu_page *root; for_each_tdp_mmu_root_yield_safe(kvm, root, as_id) - flush = tdp_mmu_zap_leafs(kvm, root, start, end, can_yield, false); + flush = tdp_mmu_zap_leafs(kvm, root, start, end, can_yield, flush); return flush; } Cc: Ben Gardon <bgardon@google.com> Signed-off-by:
Vitaly Kuznetsov <vkuznets@redhat.com> Message-Id: <20220325230348.2587437-1-seanjc@google.com> Signed-off-by:
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Yi Wang authored
As guest_irq is coming from KVM_IRQFD API call, it may trigger crash in svm_update_pi_irte() due to out-of-bounds: crash> bt PID: 22218 TASK: ffff951a6ad74980 CPU: 73 COMMAND: "vcpu8" #0 [ffffb1ba6707fa40] machine_kexec at ffffffff8565b397 #1 [ffffb1ba6707fa90] __crash_kexec at ffffffff85788a6d #2 [ffffb1ba6707fb58] crash_kexec at ffffffff8578995d #3 [ffffb1ba6707fb70] oops_end at ffffffff85623c0d #4 [ffffb1ba6707fb90] no_context at ffffffff856692c9 #5 [ffffb1ba6707fbf8] exc_page_fault at ffffffff85f95b51 #6 [ffffb1ba6707fc50] asm_exc_page_fault at ffffffff86000ace [exception RIP: svm_update_pi_irte+227] RIP: ffffffffc0761b53 RSP: ffffb1ba6707fd08 RFLAGS: 00010086 RAX: ffffb1ba6707fd78 RBX: ffffb1ba66d91000 RCX: 0000000000000001 RDX: 00003c803f63f1c0 RSI: 000000000000019a RDI: ffffb1ba66db2ab8 RBP: 000000000000019a R8: 0000000000000040 R9: ffff94ca41b82200 R10: ffffffffffffffcf R11: 0000000000000001 R12: 0000000000000001 R13: 0000000000000001 R14: ffffffffffffffcf R15: 000000000000005f ORIG_RAX: ffffffffffffffff CS: 0010 SS: 0018 #7 [ffffb1ba6707fdb8] kvm_irq_routing_update at ffffffffc09f19a1 [kvm] #8 [ffffb1ba6707fde0] kvm_set_irq_routing at ffffffffc09f2133 [kvm] #9 [ffffb1ba6707fe18] kvm_vm_ioctl at ffffffffc09ef544 [kvm] RIP: 00007f143c36488b RSP: 00007f143a4e04b8 RFLAGS: 00000246 RAX: ffffffffffffffda RBX: 00007f05780041d0 RCX: 00007f143c36488b RDX: 00007f05780041d0 RSI: 000000004008ae6a RDI: 0000000000000020 RBP: 00000000000004e8 R8: 0000000000000008 R9: 00007f05780041e0 R10: 00007f0578004560 R11: 0000000000000246 R12: 00000000000004e0 R13: 000000000000001a R14: 00007f1424001c60 R15: 00007f0578003bc0 ORIG_RAX: 0000000000000010 CS: 0033 SS: 002b Vmx have been fix this in commit 3a8b0677 (KVM: VMX: Do not BUG() on out-of-bounds guest IRQ), so we can just copy source from that to fix this. Co-developed-by:Yi Liu <liu.yi24@zte.com.cn> Signed-off-by:
Yi Wang <wang.yi59@zte.com.cn> Message-Id: <20220309113025.44469-1-wang.yi59@zte.com.cn> Cc: stable@vger.kernel.org Signed-off-by:
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Paolo Bonzini authored
If kvm->arch.tdp_mmu_zap_wq cannot be created, the failure has to be propagated up to kvm_mmu_init_vm and kvm_arch_init_vm. kvm_arch_init_vm also has to undo all the initialization, so group all the MMU initialization code at the beginning and handle cleaning up of kvm_page_track_init. Signed-off-by:
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- 29 Mar, 2022 11 commits
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Vitaly Kuznetsov authored
Setting non-zero values to SYNIC/STIMER MSRs activates certain features, this should not happen when KVM_CAP_HYPERV_SYNIC{,2} was not activated. Note, it would've been better to forbid writing anything to SYNIC/STIMER MSRs, including zeroes, however, at least QEMU tries clearing HV_X64_MSR_STIMER0_CONFIG without SynIC. HV_X64_MSR_EOM MSR is somewhat 'special' as writing zero there triggers an action, this also should not happen when SynIC wasn't activated. Signed-off-by: -
Vitaly Kuznetsov authored
When kvm_irq_delivery_to_apic_fast() is called with APIC_DEST_SELF shorthand, 'src' must not be NULL. Crash the VM with KVM_BUG_ON() instead of crashing the host. Signed-off-by:
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Vitaly Kuznetsov authored
When KVM_CAP_HYPERV_SYNIC{,2} is activated, KVM already checks for irqchip_in_kernel() so normally SynIC irqs should never be set. It is, however, possible for a misbehaving VMM to write to SYNIC/STIMER MSRs causing erroneous behavior. The immediate issue being fixed is that kvm_irq_delivery_to_apic() (kvm_irq_delivery_to_apic_fast()) crashes when called with 'irq.shorthand = APIC_DEST_SELF' and 'src == NULL'. Signed-off-by: -
Paolo Bonzini authored
Add a section to document all the different ways in which the KVM API sucks. I am sure there are way more, give people a place to vent so that userspace authors are aware. Signed-off-by:
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Paolo Bonzini authored
Add a file to document all the different ways in which the virtual CPU emulation is imperfect. Include an example to show how to document such errata. Signed-off-by:
Oliver Upton <oupton@google.com> Message-Id: <20220322110712.222449-3-pbonzini@redhat.com> Signed-off-by:
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Paolo Bonzini authored
ARM already has an arm/ subdirectory, but s390 and x86 do not even though they have a relatively large number of files specific to them. Create new directories in Documentation/virt/kvm for these two architectures as well. While at it, group the API documentation and the developer documentation in the table of contents. Signed-off-by:
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Paolo Bonzini authored
kvm->mn_invalidate_lock and kvm->slots_arch_lock were not included in the documentation, add them. Signed-off-by:
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Paolo Bonzini authored
Separate the various locks clearly, and include the new names of blocked_vcpu_on_cpu_lock and blocked_vcpu_on_cpu. Signed-off-by:
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Nathan Chancellor authored
Clang warns: arch/x86/kvm/cpuid.c:739:2: error: unannotated fall-through between switch labels [-Werror,-Wimplicit-fallthrough] default: ^ arch/x86/kvm/cpuid.c:739:2: note: insert 'break;' to avoid fall-through default: ^ break; 1 error generated. Clang is a little more pedantic than GCC, which does not warn when falling through to a case that is just break or return. Clang's version is more in line with the kernel's own stance in deprecated.rst, which states that all switch/case blocks must end in either break, fallthrough, continue, goto, or return. Add the missing break to silence the warning. Fixes: f144c49e ("KVM: x86: synthesize CPUID leaf 0x80000021h if useful") Reported-by:kernel test robot <lkp@intel.com> Signed-off-by:
Nathan Chancellor <nathan@kernel.org> Message-Id: <20220322152906.112164-1-nathan@kernel.org> Signed-off-by:
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David Matlack authored
This reverts commit 3d3aab1b. Now that the KVM module's lifetime is tied to kvm.users_count, there is no need to also tie it's lifetime to the lifetime of the VM and vCPU file descriptors. Suggested-by:
David Matlack <dmatlack@google.com> Message-Id: <20220303183328.1499189-3-dmatlack@google.com> Reviewed-by:
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David Matlack authored
Tie the lifetime the KVM module to the lifetime of each VM via kvm.users_count. This way anything that grabs a reference to the VM via kvm_get_kvm() cannot accidentally outlive the KVM module. Prior to this commit, the lifetime of the KVM module was tied to the lifetime of /dev/kvm file descriptors, VM file descriptors, and vCPU file descriptors by their respective file_operations "owner" field. This approach is insufficient because references grabbed via kvm_get_kvm() do not prevent closing any of the aforementioned file descriptors. This fixes a long standing theoretical bug in KVM that at least affects async page faults. kvm_setup_async_pf() grabs a reference via kvm_get_kvm(), and drops it in an asynchronous work callback. Nothing prevents the VM file descriptor from being closed and the KVM module from being unloaded before this callback runs. Fixes: af585b92 ("KVM: Halt vcpu if page it tries to access is swapped out") Fixes: 3d3aab1b ("KVM: set owner of cpu and vm file operations") Cc: stable@vger.kernel.org Suggested-by:
Ben Gardon <bgardon@google.com> [ Based on a patch from Ben implemented for Google's kernel. ] Signed-off-by:
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- 21 Mar, 2022 8 commits
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Paolo Bonzini authored
Instead of using array_size, use a function that takes care of the multiplication. While at it, switch to kvcalloc since this allocation should not be very large. Signed-off-by: -
Oliver Upton authored
KVM_CAP_DISABLE_QUIRKS is irrevocably broken. The capability does not advertise the set of quirks which may be disabled to userspace, so it is impossible to predict the behavior of KVM. Worse yet, KVM_CAP_DISABLE_QUIRKS will tolerate any value for cap->args[0], meaning it fails to reject attempts to set invalid quirk bits. The only valid workaround for the quirky quirks API is to add a new CAP. Actually advertise the set of quirks that can be disabled to userspace so it can predict KVM's behavior. Reject values for cap->args[0] that contain invalid bits. Finally, add documentation for the new capability and describe the existing quirks. Signed-off-by:
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Thomas Gleixner authored
Non constant TSC is a nightmare on bare metal already, but with virtualization it becomes a complete disaster because the workarounds are horrible latency wise. That's also a preliminary for running RT in a guest on top of a RT host. Signed-off-by:
Thomas Gleixner <tglx@linutronix.de> Signed-off-by:
Sebastian Andrzej Siewior <bigeasy@linutronix.de> Message-Id: <Yh5eJSG19S2sjZfy@linutronix.de> Signed-off-by:
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Paolo Bonzini authored
Guests X86_BUG_NULL_SEG if and only if the host has them. Use the info from static_cpu_has_bug to form the 0x80000021 CPUID leaf that was defined for Zen3. Userspace can then set the bit even on older CPUs that do not have the bug, such as Zen2. Do the same for X86_FEATURE_LFENCE_RDTSC as well, since various processors have had very different ways of detecting it and not all of them are available to userspace. Signed-off-by: -
Paolo Bonzini authored
CPUID leaf 0x80000021 defines some features (or lack of bugs) of AMD processors. Expose the ones that make sense via KVM_GET_SUPPORTED_CPUID. Signed-off-by: -
Maxim Levitsky authored
KVM_X86_OP_OPTIONAL_RET0 can only be used with 32-bit return values on 32-bit systems, because unsigned long is only 32-bits wide there and 64-bit values are returned in edx:eax. Reported-by:
Maxim Levitsky <mlevitsk@redhat.com> Signed-off-by:
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Paolo Bonzini authored
This reverts commit cf3e2642. Multi-vCPU Hyper-V guests started crashing randomly on boot with the latest kvm/queue and the problem can be bisected the problem to this particular patch. Basically, I'm not able to boot e.g. 16-vCPU guest successfully anymore. Both Intel and AMD seem to be affected. Reverting the commit saves the day. Reported-by:
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Paolo Bonzini authored
Since "KVM: x86/mmu: Zap only TDP MMU leafs in kvm_zap_gfn_range()" is going to be reverted, it's not going to be true anymore that the zap-page flow does not free any 'struct kvm_mmu_page'. Introduce an early flush before tdp_mmu_zap_leafs() returns, to preserve bisectability. Signed-off-by:
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- 18 Mar, 2022 3 commits
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git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarmPaolo Bonzini authored
KVM/arm64 updates for 5.18 - Proper emulation of the OSLock feature of the debug architecture - Scalibility improvements for the MMU lock when dirty logging is on - New VMID allocator, which will eventually help with SVA in VMs - Better support for PMUs in heterogenous systems - PSCI 1.1 support, enabling support for SYSTEM_RESET2 - Implement CONFIG_DEBUG_LIST at EL2 - Make CONFIG_ARM64_ERRATUM_2077057 default y - Reduce the overhead of VM exit when no interrupt is pending - Remove traces of 32bit ARM host support from the documentation - Updated vgic selftests - Various cleanups, doc updates and spelling fixes
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Julia Lawall authored
Various spelling mistakes in comments. Detected with the help of Coccinelle. Signed-off-by:
Julia Lawall <Julia.Lawall@inria.fr> Signed-off-by:
Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20220318103729.157574-24-Julia.Lawall@inria.fr
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Marc Zyngier authored
We currently deal with a set of booleans for VM features, while they could be better represented as set of flags contained in an unsigned long, similarily to what we are doing on the CPU side. Signed-off-by:
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- 15 Mar, 2022 1 commit
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https://github.com/kvm-riscv/linuxPaolo Bonzini authored
KVM/riscv changes for 5.18 - Prevent KVM_COMPAT from being selected - Refine __kvm_riscv_switch_to() implementation - RISC-V SBI v0.3 support
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