From: Paolo Bonzini <pbonzini@redhat.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
nathan@kernel.org, thomas.lendacky@amd.com,
andrew.cooper3@citrix.com, jmattson@google.com,
seanjc@google.com, stable@vger.kernel.org
Subject: Re: [PATCH 4/8] KVM: SVM: move guest vmsave/vmload to assembly
Date: Mon, 7 Nov 2022 16:40:23 +0100 [thread overview]
Message-ID: <4427cc5b-82fd-5656-da68-186b87dbe666@redhat.com> (raw)
In-Reply-To: <Y2ki4Iz8AZzTODKS@hirez.programming.kicks-ass.net>
On 11/7/22 16:23, Peter Zijlstra wrote:
>>
>> +3: vmrun %_ASM_AX
>> +4:
>> + cli
>>
>> + /* Pop @svm to RAX while it's the only available register. */
>> pop %_ASM_AX
>>
>> /* Save all guest registers. */
> So Andrew noted that once the vmload has executed any exception taken
> (say at 3) will crash and burn because %gs is scribbled.
>
> Might be good to make a record of this in the code so it can be cleaned
> up some day.
>
Yeah, it won't happen because clgi/stgi blocks setting kvm_rebooting so
I thought of killing the three exception fixups after the first. In the
end I kept them for simplicity and to keep the normal/SEV-ES versions as
similar as possible.
Paolo
next prev parent reply other threads:[~2022-11-07 15:41 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-11-07 14:54 [PATCH 0/8] KVM: SVM: fixes for vmentry code Paolo Bonzini
2022-11-07 14:54 ` [PATCH 1/8] KVM: SVM: extract VMCB accessors to a new file Paolo Bonzini
2022-11-07 17:08 ` Sean Christopherson
2022-11-07 17:36 ` Paolo Bonzini
2022-11-07 18:14 ` Sean Christopherson
2022-11-07 18:51 ` Paolo Bonzini
2022-11-08 8:52 ` Paolo Bonzini
2022-11-07 14:54 ` [PATCH 2/8] KVM: SVM: replace regs argument of __svm_vcpu_run with vcpu_svm Paolo Bonzini
2022-11-07 17:10 ` Sean Christopherson
2022-11-07 17:22 ` Paolo Bonzini
2022-11-07 14:54 ` [PATCH 3/8] KVM: SVM: adjust register allocation for __svm_vcpu_run Paolo Bonzini
2022-11-07 14:54 ` [PATCH 4/8] KVM: SVM: move guest vmsave/vmload to assembly Paolo Bonzini
2022-11-07 15:23 ` Peter Zijlstra
2022-11-07 15:40 ` Paolo Bonzini [this message]
2022-11-07 15:32 ` Andrew Cooper
2022-11-07 15:37 ` Paolo Bonzini
2022-11-07 15:47 ` Andrew Cooper
2022-11-07 14:54 ` [PATCH 5/8] KVM: SVM: retrieve VMCB from assembly Paolo Bonzini
2022-11-07 14:54 ` [PATCH 6/8] KVM: SVM: restore host save area " Paolo Bonzini
2022-11-07 14:54 ` [PATCH 7/8] KVM: SVM: move MSR_IA32_SPEC_CTRL save/restore to assembly Paolo Bonzini
2022-11-07 18:45 ` Jim Mattson
2022-11-07 19:08 ` Paolo Bonzini
2022-11-09 21:23 ` Jim Mattson
2022-11-07 14:54 ` [PATCH 8/8] x86, KVM: remove unnecessary argument to x86_virt_spec_ctrl and callers Paolo Bonzini
2022-11-07 15:33 ` [PATCH 0/8] KVM: SVM: fixes for vmentry code Peter Zijlstra
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