diff options
author | Maxim Levitsky <mlevitsk@redhat.com> | 2021-11-15 15:18:37 +0200 |
---|---|---|
committer | Paolo Bonzini <pbonzini@redhat.com> | 2021-11-18 02:03:42 -0500 |
commit | b8453cdcf26020030da182f0156d7bf59ae5719f (patch) | |
tree | 40b891fefa34a57ea3a7e015cb6a7dc2219036f7 /arch/x86 | |
parent | af957eebfcc17433ee83ab85b1195a933ab5049c (diff) |
KVM: x86/mmu: include EFER.LMA in extended mmu role
Incorporate EFER.LMA into kvm_mmu_extended_role, as it used to compute the
guest root level and is not reflected in kvm_mmu_page_role.level when TDP
is in use. When simply running the guest, it is impossible for EFER.LMA
and kvm_mmu.root_level to get out of sync, as the guest cannot transition
from PAE paging to 64-bit paging without toggling CR0.PG, i.e. without
first bouncing through a different MMU context. And stuffing guest state
via KVM_SET_SREGS{,2} also ensures a full MMU context reset.
However, if KVM_SET_SREGS{,2} is followed by KVM_SET_NESTED_STATE, e.g. to
set guest state when migrating the VM while L2 is active, the vCPU state
will reflect L2, not L1. If L1 is using TDP for L2, then root_mmu will
have been configured using L2's state, despite not being used for L2. If
L2.EFER.LMA != L1.EFER.LMA, and L2 is using PAE paging, then root_mmu will
be configured for guest PAE paging, but will match the mmu_role for 64-bit
paging and cause KVM to not reconfigure root_mmu on the next nested VM-Exit.
Alternatively, the root_mmu's role could be invalidated after a successful
KVM_SET_NESTED_STATE that yields vcpu->arch.mmu != vcpu->arch.root_mmu,
i.e. that switches the active mmu to guest_mmu, but doing so is unnecessarily
tricky, and not even needed if L1 and L2 do have the same role (e.g., they
are both 64-bit guests and run with the same CR4).
Suggested-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
Message-Id: <20211115131837.195527-3-mlevitsk@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86')
-rw-r--r-- | arch/x86/include/asm/kvm_host.h | 1 | ||||
-rw-r--r-- | arch/x86/kvm/mmu/mmu.c | 1 |
2 files changed, 2 insertions, 0 deletions
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index 33e3292233f3..e977634333d4 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -363,6 +363,7 @@ union kvm_mmu_extended_role { unsigned int cr4_smap:1; unsigned int cr4_smep:1; unsigned int cr4_la57:1; + unsigned int efer_lma:1; }; }; diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index 04c00c34517e..0571b1c7bf6f 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -4682,6 +4682,7 @@ static union kvm_mmu_extended_role kvm_calc_mmu_role_ext(struct kvm_vcpu *vcpu, /* PKEY and LA57 are active iff long mode is active. */ ext.cr4_pke = ____is_efer_lma(regs) && ____is_cr4_pke(regs); ext.cr4_la57 = ____is_efer_lma(regs) && ____is_cr4_la57(regs); + ext.efer_lma = ____is_efer_lma(regs); } ext.valid = 1; |