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author | Linus Torvalds <torvalds@linux-foundation.org> | 2024-03-10 19:27:39 +0300 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2024-03-10 19:27:39 +0300 |
commit | 137e0ec05aeb657472d2f84dbb3081016160334b (patch) | |
tree | 14968f4e17b9c8c961b78fdb51c78266cc5fa772 /include | |
parent | 005f6f34bd47eaa61d939a2727fc648e687b84c1 (diff) | |
parent | 5abf6dceb066f2b02b225fd561440c98a8062681 (diff) | |
download | linux-137e0ec05aeb657472d2f84dbb3081016160334b.tar.xz |
Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm
Pull kvm fixes from Paolo Bonzini:
"KVM GUEST_MEMFD fixes for 6.8:
- Make KVM_MEM_GUEST_MEMFD mutually exclusive with KVM_MEM_READONLY
to avoid creating an inconsistent ABI (KVM_MEM_GUEST_MEMFD is not
writable from userspace, so there would be no way to write to a
read-only guest_memfd).
- Update documentation for KVM_SW_PROTECTED_VM to make it abundantly
clear that such VMs are purely for development and testing.
- Limit KVM_SW_PROTECTED_VM guests to the TDP MMU, as the long term
plan is to support confidential VMs with deterministic private
memory (SNP and TDX) only in the TDP MMU.
- Fix a bug in a GUEST_MEMFD dirty logging test that caused false
passes.
x86 fixes:
- Fix missing marking of a guest page as dirty when emulating an
atomic access.
- Check for mmu_notifier invalidation events before faulting in the
pfn, and before acquiring mmu_lock, to avoid unnecessary work and
lock contention with preemptible kernels (including
CONFIG_PREEMPT_DYNAMIC in non-preemptible mode).
- Disable AMD DebugSwap by default, it breaks VMSA signing and will
be re-enabled with a better VM creation API in 6.10.
- Do the cache flush of converted pages in svm_register_enc_region()
before dropping kvm->lock, to avoid a race with unregistering of
the same region and the consequent use-after-free issue"
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
SEV: disable SEV-ES DebugSwap by default
KVM: x86/mmu: Retry fault before acquiring mmu_lock if mapping is changing
KVM: SVM: Flush pages under kvm->lock to fix UAF in svm_register_enc_region()
KVM: selftests: Add a testcase to verify GUEST_MEMFD and READONLY are exclusive
KVM: selftests: Create GUEST_MEMFD for relevant invalid flags testcases
KVM: x86/mmu: Restrict KVM_SW_PROTECTED_VM to the TDP MMU
KVM: x86: Update KVM_SW_PROTECTED_VM docs to make it clear they're a WIP
KVM: Make KVM_MEM_GUEST_MEMFD mutually exclusive with KVM_MEM_READONLY
KVM: x86: Mark target gfn of emulated atomic instruction as dirty
Diffstat (limited to 'include')
-rw-r--r-- | include/linux/kvm_host.h | 26 |
1 files changed, 26 insertions, 0 deletions
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index 7e7fd25b09b3..179df96b20f8 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -2031,6 +2031,32 @@ static inline int mmu_invalidate_retry_gfn(struct kvm *kvm, return 1; return 0; } + +/* + * This lockless version of the range-based retry check *must* be paired with a + * call to the locked version after acquiring mmu_lock, i.e. this is safe to + * use only as a pre-check to avoid contending mmu_lock. This version *will* + * get false negatives and false positives. + */ +static inline bool mmu_invalidate_retry_gfn_unsafe(struct kvm *kvm, + unsigned long mmu_seq, + gfn_t gfn) +{ + /* + * Use READ_ONCE() to ensure the in-progress flag and sequence counter + * are always read from memory, e.g. so that checking for retry in a + * loop won't result in an infinite retry loop. Don't force loads for + * start+end, as the key to avoiding infinite retry loops is observing + * the 1=>0 transition of in-progress, i.e. getting false negatives + * due to stale start+end values is acceptable. + */ + if (unlikely(READ_ONCE(kvm->mmu_invalidate_in_progress)) && + gfn >= kvm->mmu_invalidate_range_start && + gfn < kvm->mmu_invalidate_range_end) + return true; + + return READ_ONCE(kvm->mmu_invalidate_seq) != mmu_seq; +} #endif #ifdef CONFIG_HAVE_KVM_IRQ_ROUTING |