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,
Tom Lendacky <thomas.lendacky@amd.com>,
Michael Roth <michael.roth@amd.com>,
Alexey Kardashevskiy <aik@amd.com>
Subject: [PATCH 4/8] KVM: SVM: Clobber RAX instead of RBX when discarding spec_ctrl_intercepted
Date: Fri, 23 Feb 2024 12:42:29 -0800 [thread overview]
Message-ID: <20240223204233.3337324-5-seanjc@google.com> (raw)
In-Reply-To: <20240223204233.3337324-1-seanjc@google.com>
POP @spec_ctrl_intercepted into RAX instead of RBX when discarding it from
the stack so that __svm_sev_es_vcpu_run() doesn't modify any non-volatile
registers. __svm_sev_es_vcpu_run() doesn't return a value, and RAX is
already are clobbered multiple times in the #VMEXIT path.
This will allowing using the host save area to save/restore non-volatile
registers in __svm_sev_es_vcpu_run().
Signed-off-by: Sean Christopherson <seanjc@google.com>
---
arch/x86/kvm/svm/vmenter.S | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/arch/x86/kvm/svm/vmenter.S b/arch/x86/kvm/svm/vmenter.S
index 0026b4a56d25..edbaadaacba7 100644
--- a/arch/x86/kvm/svm/vmenter.S
+++ b/arch/x86/kvm/svm/vmenter.S
@@ -350,8 +350,8 @@ SYM_FUNC_START(__svm_sev_es_vcpu_run)
*/
UNTRAIN_RET_VM
- /* "Pop" @spec_ctrl_intercepted. */
- pop %rbx
+ /* "Pop" and discard @spec_ctrl_intercepted. */
+ pop %rax
pop %rbx
--
2.44.0.rc0.258.g7320e95886-goog
next prev parent reply other threads:[~2024-02-23 20:42 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-02-23 20:42 [PATCH 0/8] KVM: SVM: Clean up VMRUN=>#VMEXIT assembly Sean Christopherson
2024-02-23 20:42 ` [PATCH 1/8] KVM: SVM: Create a stack frame in __svm_vcpu_run() for unwinding Sean Christopherson
2024-02-23 20:42 ` [PATCH 2/8] KVM: SVM: Wrap __svm_sev_es_vcpu_run() with #ifdef CONFIG_KVM_AMD_SEV Sean Christopherson
2024-02-23 20:42 ` [PATCH 3/8] KVM: SVM: Drop 32-bit "support" from __svm_sev_es_vcpu_run() Sean Christopherson
2024-02-23 20:42 ` Sean Christopherson [this message]
2024-02-23 20:42 ` [PATCH 5/8] KVM: SVM: Save/restore non-volatile GPRs in SEV-ES VMRUN via host save area Sean Christopherson
2024-02-23 20:42 ` [PATCH 6/8] KVM: SVM: Save/restore args across " Sean Christopherson
2024-02-23 20:42 ` [PATCH 7/8] KVM: SVM: Create a stack frame in __svm_sev_es_vcpu_run() Sean Christopherson
2024-02-23 20:42 ` [PATCH 8/8] KVM: x86: Stop compiling vmenter.S with OBJECT_FILES_NON_STANDARD Sean Christopherson
2024-02-26 20:02 ` [PATCH 0/8] KVM: SVM: Clean up VMRUN=>#VMEXIT assembly Tom Lendacky
2024-04-10 0:19 ` Sean Christopherson
2024-04-17 12:58 ` Paolo Bonzini
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