From: Sean Christopherson <seanjc@google.com>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
thomas.lendacky@amd.com, jmattson@google.com,
stable@vger.kernel.org
Subject: Re: [PATCH 03/11] KVM: SVM: adjust register allocation for __svm_vcpu_run
Date: Wed, 9 Nov 2022 15:20:01 +0000 [thread overview]
Message-ID: <Y2vFIR+T+9SFY0xO@google.com> (raw)
In-Reply-To: <20221109145156.84714-4-pbonzini@redhat.com>
On Wed, Nov 09, 2022, Paolo Bonzini wrote:
> In preparation for moving vmload/vmsave to __svm_vcpu_run,
__svm_vcpu_run()
> keep the pointer to the struct vcpu_svm in %rdi. This way
> it is possible to load svm->vmcb01.pa in %rax without
> clobbering the pointer to svm itself.
If you feel like doing fixup before pushing, add a note to call out that avoiding
RAX will also be "necessary" to play nice with loading/storing MSR_SPEC_CTRL?
When fiddling with this code, I found the RDMSR/WRMSR clobbers to be far more
problematic than the VMCB pointers.
> No functional change intended.
>
> Cc: stable@vger.kernel.org
> Fixes: a149180fbcf3 ("x86: Add magic AMD return-thunk")
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Sean Christopherson <seanjc@google.com>
next prev parent reply other threads:[~2022-11-09 15:20 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-11-09 14:51 [PATCH v3 00/11] KVM: SVM: fixes for vmentry code Paolo Bonzini
2022-11-09 14:51 ` [PATCH 01/11] KVM: x86: use a separate asm-offsets.c file Paolo Bonzini
2022-11-09 15:06 ` Sean Christopherson
2022-11-09 14:51 ` [PATCH 02/11] KVM: SVM: replace regs argument of __svm_vcpu_run with vcpu_svm Paolo Bonzini
2022-11-09 15:14 ` Sean Christopherson
2022-11-09 14:51 ` [PATCH 03/11] KVM: SVM: adjust register allocation for __svm_vcpu_run Paolo Bonzini
2022-11-09 15:20 ` Sean Christopherson [this message]
2022-11-09 16:04 ` Paolo Bonzini
2022-11-09 14:51 ` [PATCH 04/11] KVM: SVM: retrieve VMCB from assembly Paolo Bonzini
2022-11-09 15:25 ` Sean Christopherson
2022-11-09 14:51 ` [PATCH 05/11] KVM: SVM: remove unused field from struct vcpu_svm Paolo Bonzini
2022-11-09 15:25 ` Sean Christopherson
2022-11-09 14:51 ` [PATCH 06/11] KVM: SVM: remove dead field from struct svm_cpu_data Paolo Bonzini
2022-11-09 15:26 ` Sean Christopherson
2022-11-09 14:51 ` [PATCH 07/11] KVM: SVM: do not allocate struct svm_cpu_data dynamically Paolo Bonzini
2022-11-09 15:58 ` Sean Christopherson
2022-11-09 16:00 ` Paolo Bonzini
2022-11-09 14:51 ` [PATCH 08/11] KVM: SVM: move guest vmsave/vmload back to assembly Paolo Bonzini
2022-11-09 15:29 ` Sean Christopherson
2022-11-09 14:51 ` [PATCH 09/11] KVM: SVM: restore host save area from assembly Paolo Bonzini
2022-11-09 15:54 ` Sean Christopherson
2022-11-09 14:51 ` [PATCH 10/11] KVM: SVM: move MSR_IA32_SPEC_CTRL save/restore to assembly Paolo Bonzini
2022-11-09 16:04 ` Sean Christopherson
2022-11-09 14:51 ` [PATCH 11/11] x86, KVM: remove unnecessary argument to x86_virt_spec_ctrl and callers Paolo Bonzini
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