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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,
	 Peter Gonda <pgonda@google.com>,
	Michael Roth <michael.roth@amd.com>,
	 Vishal Annapurve <vannapurve@google.com>,
	Ackerly Tng <ackerleytng@google.com>
Subject: [PATCH 06/22] KVM: x86: Get RIP from vCPU state when storing it to last_retry_eip
Date: Fri,  9 Aug 2024 12:03:03 -0700	[thread overview]
Message-ID: <20240809190319.1710470-7-seanjc@google.com> (raw)
In-Reply-To: <20240809190319.1710470-1-seanjc@google.com>

Read RIP from vCPU state instead of pulling it from the emulation context
when filling last_retry_eip, which is part of the anti-infinite-loop
protection used when unprotecting and retrying instructions that hit a
write-protected gfn.

This will allow reusing the anti-infinite-loop protection in flows that
never make it into the emulator.

This is a glorified nop as ctxt->eip is set to kvm_rip_read() in
init_emulate_ctxt(), and EMULTYPE_PF emulation is mutually exclusive with
EMULTYPE_NO_DECODE and EMULTYPE_SKIP, i.e. always goes through
x86_decode_emulated_instruction() and hasn't advanced ctxt->eip (yet).

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

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 2072cceac68f..372ed3842732 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -8973,7 +8973,7 @@ static bool retry_instruction(struct x86_emulate_ctxt *ctxt,
 	if (!kvm_mmu_unprotect_page(vcpu->kvm, gpa_to_gfn(gpa)))
 		return false;
 
-	vcpu->arch.last_retry_eip = ctxt->eip;
+	vcpu->arch.last_retry_eip = kvm_rip_read(vcpu);
 	vcpu->arch.last_retry_addr = cr2_or_gpa;
 	return true;
 }
-- 
2.46.0.76.ge559c4bf1a-goog


  parent reply	other threads:[~2024-08-09 19:03 UTC|newest]

Thread overview: 53+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-08-09 19:02 [PATCH 00/22] KVM: x86: Fix multiple #PF RO infinite loop bugs Sean Christopherson
2024-08-09 19:02 ` [PATCH 01/22] KVM: x86: Disallow read-only memslots for SEV-ES and SEV-SNP (and TDX) Sean Christopherson
2024-08-14 16:31   ` Paolo Bonzini
2025-12-03 13:04   ` Naveen N Rao
2025-12-23 16:06     ` Sean Christopherson
2024-08-09 19:02 ` [PATCH 02/22] KVM: VMX: Set PFERR_GUEST_{FINAL,PAGE}_MASK if and only if the GVA is valid Sean Christopherson
2024-08-14 11:11   ` Yuan Yao
2024-08-09 19:03 ` [PATCH 03/22] KVM: x86/mmu: Trigger unprotect logic only on write-protection page faults Sean Christopherson
2024-08-14 11:42   ` Yuan Yao
2024-08-14 14:21     ` Sean Christopherson
2024-08-15  8:30       ` Yuan Yao
2024-08-14 16:40   ` Paolo Bonzini
2024-08-14 19:34     ` Sean Christopherson
2024-08-09 19:03 ` [PATCH 04/22] KVM: x86/mmu: Skip emulation on page fault iff 1+ SPs were unprotected Sean Christopherson
2024-08-14 14:22   ` Yuan Yao
2024-08-15 23:31     ` Yao Yuan
2024-08-23  0:39       ` Sean Christopherson
2024-08-23 23:46         ` Sean Christopherson
2024-08-26 20:28           ` Sean Christopherson
2024-08-14 16:47   ` Paolo Bonzini
2024-08-09 19:03 ` [PATCH 05/22] KVM: x86: Retry to-be-emulated insn in "slow" unprotect path iff sp is zapped Sean Christopherson
2024-08-09 19:03 ` Sean Christopherson [this message]
2024-08-14 17:01   ` [PATCH 06/22] KVM: x86: Get RIP from vCPU state when storing it to last_retry_eip Paolo Bonzini
2024-08-09 19:03 ` [PATCH 07/22] KVM: x86: Store gpa as gpa_t, not unsigned long, when unprotecting for retry Sean Christopherson
2024-08-09 19:03 ` [PATCH 08/22] KVM: x86/mmu: Apply retry protection to "fast nTDP unprotect" path Sean Christopherson
2024-08-09 19:03 ` [PATCH 09/22] KVM: x86/mmu: Try "unprotect for retry" iff there are indirect SPs Sean Christopherson
2024-08-14 17:30   ` Paolo Bonzini
2024-08-15 14:09     ` Sean Christopherson
2024-08-15 16:48       ` Paolo Bonzini
2024-08-28 23:28         ` Sean Christopherson
2024-08-09 19:03 ` [PATCH 10/22] KVM: x86/mmu: Replace PFERR_NESTED_GUEST_PAGE with a more descriptive helper Sean Christopherson
2024-08-14 17:32   ` Paolo Bonzini
2024-08-15 14:10     ` Sean Christopherson
2024-08-09 19:03 ` [PATCH 11/22] KVM: x86: Move EMULTYPE_ALLOW_RETRY_PF to x86_emulate_instruction() Sean Christopherson
2024-08-09 19:03 ` [PATCH 12/22] KVM: x86: Fold retry_instruction() into x86_emulate_instruction() Sean Christopherson
2024-08-09 19:03 ` [PATCH 13/22] KVM: x86/mmu: Don't try to unprotect an INVALID_GPA Sean Christopherson
2024-08-09 19:03 ` [PATCH 14/22] KVM: x86/mmu: Always walk guest PTEs with WRITE access when unprotecting Sean Christopherson
2024-08-09 19:03 ` [PATCH 15/22] KVM: x86/mmu: Move event re-injection unprotect+retry into common path Sean Christopherson
2024-08-14 17:43   ` Paolo Bonzini
2024-08-26 21:52     ` Sean Christopherson
2024-08-09 19:03 ` [PATCH 16/22] KVM: x86: Remove manual pfn lookup when retrying #PF after failed emulation Sean Christopherson
2024-08-14 17:50   ` Paolo Bonzini
2024-08-09 19:03 ` [PATCH 17/22] KVM: x86: Check EMULTYPE_WRITE_PF_TO_SP before unprotecting gfn Sean Christopherson
2024-08-14 17:53   ` Paolo Bonzini
2024-08-09 19:03 ` [PATCH 18/22] KVM: x86: Apply retry protection to "unprotect on failure" path Sean Christopherson
2024-08-09 19:03 ` [PATCH 19/22] KVM: x86: Update retry protection fields when forcing retry on emulation failure Sean Christopherson
2024-08-09 19:03 ` [PATCH 20/22] KVM: x86: Rename reexecute_instruction()=>kvm_unprotect_and_retry_on_failure() Sean Christopherson
2024-08-09 19:03 ` [PATCH 21/22] KVM: x86/mmu: Subsume kvm_mmu_unprotect_page() into the and_retry() version Sean Christopherson
2024-08-09 19:03 ` [PATCH 22/22] KVM: x86/mmu: Detect if unprotect will do anything based on invalid_list Sean Christopherson
2024-08-14 17:57   ` Paolo Bonzini
2024-08-15 14:25     ` Sean Christopherson
2024-08-30 23:54       ` Sean Christopherson
2024-08-14 17:58 ` [PATCH 00/22] KVM: x86: Fix multiple #PF RO infinite loop bugs Paolo Bonzini

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