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
Subject: [PATCH v2 02/11] KVM: nSVM: Pass next RIP, not current RIP, for nested VM-Exit on emulation
Date: Fri, 31 Jan 2025 17:55:09 -0800 [thread overview]
Message-ID: <20250201015518.689704-3-seanjc@google.com> (raw)
In-Reply-To: <20250201015518.689704-1-seanjc@google.com>
Set "next_rip" in the emulation interception info passed to vendor code
using the emulator context's "_eip", not "eip". "eip" holds RIP from the
start of emulation, i.e. the RIP of the instruction that's being emulated,
whereas _eip tracks the context's current position in decoding the code
stream, which at the time of the intercept checks is effectively the RIP
of the next instruction.
Passing the current RIP as next_rip causes SVM to stuff the wrong value
value into vmcb12->control.next_rip if a nested VM-Exit is generated, i.e.
if L1 wants to intercept the instruction, and could result in L1 putting
L2 into an infinite loop due to restarting L2 with the same RIP over and
over.
Fixes: 8a76d7f25f8f ("KVM: x86: Add x86 callback for intercept check")
Signed-off-by: Sean Christopherson <seanjc@google.com>
---
arch/x86/kvm/emulate.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index 60986f67c35a..0915b5e8aa71 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -478,7 +478,7 @@ static int emulator_check_intercept(struct x86_emulate_ctxt *ctxt,
.src_bytes = ctxt->src.bytes,
.dst_bytes = ctxt->dst.bytes,
.ad_bytes = ctxt->ad_bytes,
- .next_rip = ctxt->eip,
+ .next_rip = ctxt->_eip,
};
return ctxt->ops->intercept(ctxt, &info, stage);
--
2.48.1.362.g079036d154-goog
next prev parent reply other threads:[~2025-02-01 1:55 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-02-01 1:55 [PATCH v2 00/11] KVM: x86: Fix emulation of (some) L2 instructions Sean Christopherson
2025-02-01 1:55 ` [PATCH v2 01/11] KVM: nVMX: Check PAUSE_EXITING, not BUS_LOCK_DETECTION, on PAUSE emulation Sean Christopherson
2025-02-01 1:55 ` Sean Christopherson [this message]
2025-02-01 1:55 ` [PATCH v2 03/11] KVM: nVMX: Allow emulating RDPID on behalf of L2 Sean Christopherson
2025-02-01 1:55 ` [PATCH v2 04/11] KVM: nVMX: Emulate HLT in L2 if it's not intercepted Sean Christopherson
2025-02-01 1:55 ` [PATCH v2 05/11] KVM: nVMX: Consolidate missing X86EMUL_INTERCEPTED logic in L2 emulation Sean Christopherson
2025-02-01 1:55 ` [PATCH v2 06/11] KVM: x86: Plumb the src/dst operand types through to .check_intercept() Sean Christopherson
2025-02-01 1:55 ` [PATCH v2 07/11] KVM: x86: Plumb the emulator's starting RIP into nested intercept checks Sean Christopherson
2025-02-01 1:55 ` [PATCH v2 08/11] KVM: x86: Add a #define for the architectural max instruction length Sean Christopherson
2025-02-01 1:55 ` [PATCH v2 09/11] KVM: nVMX: Allow the caller to provide instruction length on nested VM-Exit Sean Christopherson
2025-02-01 1:55 ` [PATCH v2 10/11] KVM: nVMX: Synthesize nested VM-Exit for supported emulation intercepts Sean Christopherson
2025-02-01 1:55 ` [PATCH v2 11/11] KVM: selftests: Add a nested (forced) emulation intercept test for x86 Sean Christopherson
2025-02-28 17:06 ` [PATCH v2 00/11] KVM: x86: Fix emulation of (some) L2 instructions Sean Christopherson
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