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From: Sean Christopherson <seanjc@google.com>
To: Sean Christopherson <seanjc@google.com>,
	Paolo Bonzini <pbonzini@redhat.com>
Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
	 Yuan Yao <yuan.yao@intel.com>,
	Yuan Yao <yuan.yao@linux.intel.com>
Subject: [PATCH v2 13/22] KVM: x86/mmu: Always walk guest PTEs with WRITE access when unprotecting
Date: Fri, 30 Aug 2024 17:15:28 -0700	[thread overview]
Message-ID: <20240831001538.336683-14-seanjc@google.com> (raw)
In-Reply-To: <20240831001538.336683-1-seanjc@google.com>

When getting a gpa from a gva to unprotect the associated gfn when an
event is awating reinjection, walk the guest PTEs for WRITE as there's no
point in unprotecting the gfn if the guest is unable to write the page,
i.e. if write-protection can't trigger emulation.

Note, the entire flow should be guarded on the access being a write, and
even better should be conditioned on actually triggering a write-protect
fault.  This will be addressed in a future commit.

Signed-off-by: Sean Christopherson <seanjc@google.com>
---
 arch/x86/kvm/mmu/mmu.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index ee288f8370de..b89e2c63b435 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -2751,7 +2751,7 @@ static int kvm_mmu_unprotect_page_virt(struct kvm_vcpu *vcpu, gva_t gva)
 	if (vcpu->arch.mmu->root_role.direct)
 		return 0;
 
-	gpa = kvm_mmu_gva_to_gpa_read(vcpu, gva, NULL);
+	gpa = kvm_mmu_gva_to_gpa_write(vcpu, gva, NULL);
 	if (gpa == INVALID_GPA)
 		return 0;
 
-- 
2.46.0.469.g59c65b2a67-goog


  parent reply	other threads:[~2024-08-31  0:16 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-08-31  0:15 [PATCH v2 00/22] KVM: x86: Fix multiple #PF RO infinite loop bugs Sean Christopherson
2024-08-31  0:15 ` [PATCH v2 01/22] KVM: VMX: Set PFERR_GUEST_{FINAL,PAGE}_MASK if and only if the GVA is valid Sean Christopherson
2024-08-31  0:15 ` [PATCH v2 02/22] KVM: x86/mmu: Replace PFERR_NESTED_GUEST_PAGE with a more descriptive helper Sean Christopherson
2024-08-31  0:15 ` [PATCH v2 03/22] KVM: x86/mmu: Trigger unprotect logic only on write-protection page faults Sean Christopherson
2024-08-31  0:15 ` [PATCH v2 04/22] KVM: x86/mmu: Skip emulation on page fault iff 1+ SPs were unprotected Sean Christopherson
2024-09-06  6:22   ` Yuan Yao
2024-08-31  0:15 ` [PATCH v2 05/22] KVM: x86: Retry to-be-emulated insn in "slow" unprotect path iff sp is zapped Sean Christopherson
2024-09-06  8:17   ` Yuan Yao
2024-08-31  0:15 ` [PATCH v2 06/22] KVM: x86: Get RIP from vCPU state when storing it to last_retry_eip Sean Christopherson
2024-08-31  0:15 ` [PATCH v2 07/22] KVM: x86: Store gpa as gpa_t, not unsigned long, when unprotecting for retry Sean Christopherson
2024-08-31  0:15 ` [PATCH v2 08/22] KVM: x86/mmu: Apply retry protection to "fast nTDP unprotect" path Sean Christopherson
2024-08-31  0:15 ` [PATCH v2 09/22] KVM: x86/mmu: Try "unprotect for retry" iff there are indirect SPs Sean Christopherson
2024-08-31  0:15 ` [PATCH v2 10/22] KVM: x86: Move EMULTYPE_ALLOW_RETRY_PF to x86_emulate_instruction() Sean Christopherson
2024-08-31  0:15 ` [PATCH v2 11/22] KVM: x86: Fold retry_instruction() into x86_emulate_instruction() Sean Christopherson
2024-08-31  0:15 ` [PATCH v2 12/22] KVM: x86/mmu: Don't try to unprotect an INVALID_GPA Sean Christopherson
2024-08-31  0:15 ` Sean Christopherson [this message]
2024-08-31  0:15 ` [PATCH v2 14/22] KVM: x86/mmu: Move event re-injection unprotect+retry into common path Sean Christopherson
2024-08-31  0:15 ` [PATCH v2 15/22] KVM: x86: Remove manual pfn lookup when retrying #PF after failed emulation Sean Christopherson
2024-08-31  0:15 ` [PATCH v2 16/22] KVM: x86: Check EMULTYPE_WRITE_PF_TO_SP before unprotecting gfn Sean Christopherson
2024-08-31  0:15 ` [PATCH v2 17/22] KVM: x86: Apply retry protection to "unprotect on failure" path Sean Christopherson
2024-08-31  0:15 ` [PATCH v2 18/22] KVM: x86: Update retry protection fields when forcing retry on emulation failure Sean Christopherson
2024-08-31  0:15 ` [PATCH v2 19/22] KVM: x86: Rename reexecute_instruction()=>kvm_unprotect_and_retry_on_failure() Sean Christopherson
2024-08-31  0:15 ` [PATCH v2 20/22] KVM: x86/mmu: Subsume kvm_mmu_unprotect_page() into the and_retry() version Sean Christopherson
2024-08-31  0:15 ` [PATCH v2 21/22] KVM: x86/mmu: Detect if unprotect will do anything based on invalid_list Sean Christopherson
2024-08-31  0:15 ` [PATCH v2 22/22] KVM: x86/mmu: WARN on MMIO cache hit when emulating write-protected gfn Sean Christopherson
2024-09-10  4:56 ` [PATCH v2 00/22] KVM: x86: Fix multiple #PF RO infinite loop bugs Sean Christopherson

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