From db574f2f96d0c9a245a9e787e3d9ec288fb2b445 Mon Sep 17 00:00:00 2001 From: Tao Su Date: Tue, 28 May 2024 18:22:34 +0800 Subject: [PATCH] KVM: x86/mmu: Don't save mmu_invalidate_seq after checking private attr Drop the second snapshot of mmu_invalidate_seq in kvm_faultin_pfn(). Before checking the mismatch of private vs. shared, mmu_invalidate_seq is saved to fault->mmu_seq, which can be used to detect an invalidation related to the gfn occurred, i.e. KVM will not install a mapping in page table if fault->mmu_seq != mmu_invalidate_seq. Currently there is a second snapshot of mmu_invalidate_seq, which may not be same as the first snapshot in kvm_faultin_pfn(), i.e. the gfn attribute may be changed between the two snapshots, but the gfn may be mapped in page table without hindrance. Therefore, drop the second snapshot as it has no obvious benefits. Fixes: f6adeae81f35 ("KVM: x86/mmu: Handle no-slot faults at the beginning of kvm_faultin_pfn()") Signed-off-by: Tao Su Message-ID: <20240528102234.2162763-1-tao1.su@linux.intel.com> Signed-off-by: Paolo Bonzini --- arch/x86/kvm/mmu/mmu.c | 3 --- 1 file changed, 3 deletions(-) diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index b7b4426a7221..8d74bdef68c1 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -4411,9 +4411,6 @@ static int kvm_faultin_pfn(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault, return RET_PF_EMULATE; } - fault->mmu_seq = vcpu->kvm->mmu_invalidate_seq; - smp_rmb(); - /* * Check for a relevant mmu_notifier invalidation event before getting * the pfn from the primary MMU, and before acquiring mmu_lock. -- 2.20.1