[PATCH 5.18 0557/1095] KVM: SVM: Stuff next_rip on emulated INT3 injection if NRIPS is supported

Greg Kroah-Hartman
2022-08-15T21:32:11Z

From: Sean Christopherson <seanjc@google.com>

[ Upstream commit 3741aec4c38fa4123ab08ae552f05366d4fd05d8 ]

If NRIPS is supported in hardware but disabled in KVM, set next_rip to
the next RIP when advancing RIP as part of emulating INT3 injection.
There is no flag to tell the CPU that KVM isn't using next_rip, and so
leaving next_rip is left as is will result in the CPU pushing garbage
onto the stack when vectoring the injected event.

Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
Fixes: 66b7138f9136 ("KVM: SVM: Emulate nRIP feature when reinjecting INT3")
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com>
Message-Id: <cd328309a3b88604daa2359ad56f36cb565ce2d4.1651440202.git.maciej.szmigiero@oracle.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
arch/x86/kvm/svm/svm.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index e4c736d74fcb..e5a154f0d2ab 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -390,6 +390,10 @@ static void svm_queue_exception(struct kvm_vcpu *vcpu)
*/
(void)svm_skip_emulated_instruction(vcpu);
rip = kvm_rip_read(vcpu);
+
+ if (boot_cpu_has(X86_FEATURE_NRIPS))
+ svm->vmcb->control.next_rip = rip;
+
svm->int3_rip = rip + svm->vmcb->save.cs.base;
svm->int3_injected = rip - old_rip;
}
@@ -3616,7 +3620,7 @@ static void svm_complete_interrupts(struct kvm_vcpu *vcpu)
/*
* If NextRIP isn't enabled, KVM must manually advance RIP prior to
* injecting the soft exception/interrupt. That advancement needs to
- * be unwound if vectoring didn't complete. Note, the _new_ event may
+ * be unwound if vectoring didn't complete. Note, the new event may
* not be the injected event, e.g. if KVM injected an INTn, the INTn
* hit a #NP in the guest, and the #NP encountered a #PF, the #NP will
* be the reported vectored event, but RIP still needs to be unwound.
--
2.35.1