summaryrefslogtreecommitdiffstats
path: root/arch/x86/kvm
diff options
context:
space:
mode:
authorPaolo Bonzini <pbonzini@redhat.com>2015-07-10 13:32:13 +0200
committerPaolo Bonzini <pbonzini@redhat.com>2015-07-23 08:30:27 +0200
commit5492830370171b6a4ede8a3bfba687a8d0f25fa5 (patch)
tree44d7c401f31b3256be49f7f8db277b18506ce2d5 /arch/x86/kvm
parent5f3d45e7f2827f48e60eb821efd909713b43ac63 (diff)
downloadop-kernel-dev-5492830370171b6a4ede8a3bfba687a8d0f25fa5.zip
op-kernel-dev-5492830370171b6a4ede8a3bfba687a8d0f25fa5.tar.gz
KVM: svm: handle KVM_X86_QUIRK_CD_NW_CLEARED in svm_get_mt_mask
We can disable CD unconditionally when there is no assigned device. KVM now forces guest PAT to all-writeback in that case, so it makes sense to also force CR0.CD=0. When there are assigned devices, emulate cache-disabled operation through the page tables. This behavior is consistent with VMX microcode, where CD/NW are not touched by vmentry/vmexit. However, keep this dependent on the quirk because OVMF enables the caches too late. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86/kvm')
-rw-r--r--arch/x86/kvm/svm.c15
1 files changed, 8 insertions, 7 deletions
diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index 8e0c084..d1a114d 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -1173,6 +1173,10 @@ static u64 svm_get_mt_mask(struct kvm_vcpu *vcpu, gfn_t gfn, bool is_mmio)
if (!is_mmio && !kvm_arch_has_assigned_device(vcpu->kvm))
return 0;
+ if (!kvm_check_has_quirk(vcpu->kvm, KVM_X86_QUIRK_CD_NW_CLEARED) &&
+ kvm_read_cr0(vcpu) & X86_CR0_CD)
+ return _PAGE_NOCACHE;
+
mtrr = kvm_mtrr_get_guest_memory_type(vcpu, gfn);
return mtrr2protval[mtrr];
}
@@ -1667,13 +1671,10 @@ static void svm_set_cr0(struct kvm_vcpu *vcpu, unsigned long cr0)
if (!vcpu->fpu_active)
cr0 |= X86_CR0_TS;
- /*
- * re-enable caching here because the QEMU bios
- * does not do it - this results in some delay at
- * reboot
- */
- if (kvm_check_has_quirk(vcpu->kvm, KVM_X86_QUIRK_CD_NW_CLEARED))
- cr0 &= ~(X86_CR0_CD | X86_CR0_NW);
+
+ /* These are emulated via page tables. */
+ cr0 &= ~(X86_CR0_CD | X86_CR0_NW);
+
svm->vmcb->save.cr0 = cr0;
mark_dirty(svm->vmcb, VMCB_CR);
update_cr0_intercept(svm);
OpenPOWER on IntegriCloud