KVM: SVM: include CR3 in initial VMSA state for SEV-ES guests

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Normally guests will set up CR3 themselves, but some guests, such as
kselftests, and potentially CONFIG_PVH guests, rely on being booted
with paging enabled and CR3 initialized to a pre-allocated page table.

Currently CR3 updates via KVM_SET_SREGS* are not loaded into the guest
VMCB until just prior to entering the guest. For SEV-ES/SEV-SNP, this
is too late, since it will have switched over to using the VMSA page
prior to that point, with the VMSA CR3 copied from the VMCB initial
CR3 value: 0.

Address this by sync'ing the CR3 value into the VMCB save area
immediately when KVM_SET_SREGS* is issued so it will find it's way into
the initial VMSA.

Suggested-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Michael Roth <michael.roth@amd.com>
Message-Id: <20211216171358.61140-10-michael.roth@amd.com>
[Remove vmx_post_set_cr3; add a remark about kvm_set_cr3 not calling the
 new hook. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

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This commit is contained in:

Michael Roth 2021-12-16 11:13:54 -06:00 • committed by Paolo Bonzini

parent 907d139318

commit 405329fc9a

5 changed files with 24 additions and 0 deletions

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arch/x86/include/asm/kvm-x86-ops.h

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arch/x86/include/asm/kvm_host.h

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arch/x86/kvm/svm/svm.c

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arch/x86/kvm/vmx/vmx.c

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arch/x86/kvm/x86.c

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