KVM: SVM: Provide an updated VMRUN invocation for SEV-ES guests

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The run sequence is different for an SEV-ES guest compared to a legacy or
even an SEV guest. The guest vCPU register state of an SEV-ES guest will
be restored on VMRUN and saved on VMEXIT. There is no need to restore the
guest registers directly and through VMLOAD before VMRUN and no need to
save the guest registers directly and through VMSAVE on VMEXIT.

Update the svm_vcpu_run() function to skip register state saving and
restoring and provide an alternative function for running an SEV-ES guest
in vmenter.S

Additionally, certain host state is restored across an SEV-ES VMRUN. As
a result certain register states are not required to be restored upon
VMEXIT (e.g. FS, GS, etc.), so only do that if the guest is not an SEV-ES
guest.

Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Message-Id: <fb1c66d32f2194e171b95fc1a8affd6d326e10c1.1607620209.git.thomas.lendacky@amd.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

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This commit is contained in:

Tom Lendacky 2020-12-10 11:10:08 -06:00 • committed by Paolo Bonzini

parent 861377730a

commit 16809ecdc1

4 changed files with 77 additions and 9 deletions

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25

arch/x86/kvm/svm/svm.c

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5

arch/x86/kvm/svm/svm.h

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50

arch/x86/kvm/svm/vmenter.S

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6

arch/x86/kvm/x86.c

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