KVM: SVM: include CR3 in initial VMSA state for SEV-ES guests
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>
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 6492329f..a9f1044 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1179,6 +1179,7 @@ int kvm_set_cr3(struct kvm_vcpu *vcpu, unsigned long cr3)
vcpu->arch.cr3 = cr3;
kvm_register_mark_dirty(vcpu, VCPU_EXREG_CR3);
+ /* Do not call post_set_cr3, we do not get here for confidential guests. */
handle_tlb_flush:
/*
@@ -10618,6 +10619,7 @@ static int __set_sregs_common(struct kvm_vcpu *vcpu, struct kvm_sregs *sregs,
*mmu_reset_needed |= kvm_read_cr3(vcpu) != sregs->cr3;
vcpu->arch.cr3 = sregs->cr3;
kvm_register_mark_dirty(vcpu, VCPU_EXREG_CR3);
+ static_call_cond(kvm_x86_post_set_cr3)(vcpu, sregs->cr3);
kvm_set_cr8(vcpu, sregs->cr8);