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| author | Sean Christopherson <seanjc@google.com> | 2021-02-12 16:50:07 -0800 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2021-02-19 03:08:32 -0500 |
| commit | c3bb9a20834ffe72d3031afe460ff03d3b3b6e90 (patch) | |
| tree | be142b09834d49462fde1ffa10d942fa181ace6c /arch/x86/kvm/vmx/vmx.c | |
| parent | 9eba50f8d7fcb61774f160890f98239fa3ab68a6 (diff) | |
| download | lwn-c3bb9a20834ffe72d3031afe460ff03d3b3b6e90.tar.gz lwn-c3bb9a20834ffe72d3031afe460ff03d3b3b6e90.zip | |
KVM: nVMX: Disable PML in hardware when running L2
Unconditionally disable PML in vmcs02, KVM emulates PML purely in the
MMU, e.g. vmx_flush_pml_buffer() doesn't even try to copy the L2 GPAs
from vmcs02's buffer to vmcs12. At best, enabling PML is a nop. At
worst, it will cause vmx_flush_pml_buffer() to record bogus GFNs in the
dirty logs.
Initialize vmcs02.GUEST_PML_INDEX such that PML writes would trigger
VM-Exit if PML was somehow enabled, skip flushing the buffer for guest
mode since the index is bogus, and freak out if a PML full exit occurs
when L2 is active.
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20210213005015.1651772-7-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86/kvm/vmx/vmx.c')
| -rw-r--r-- | arch/x86/kvm/vmx/vmx.c | 12 |
1 files changed, 10 insertions, 2 deletions
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c index 5ddaf7e4f601..559a0f16263e 100644 --- a/arch/x86/kvm/vmx/vmx.c +++ b/arch/x86/kvm/vmx/vmx.c @@ -5966,9 +5966,10 @@ static int __vmx_handle_exit(struct kvm_vcpu *vcpu, fastpath_t exit_fastpath) * updated. Another good is, in kvm_vm_ioctl_get_dirty_log, before * querying dirty_bitmap, we only need to kick all vcpus out of guest * mode as if vcpus is in root mode, the PML buffer must has been - * flushed already. + * flushed already. Note, PML is never enabled in hardware while + * running L2. */ - if (enable_pml) + if (enable_pml && !is_guest_mode(vcpu)) vmx_flush_pml_buffer(vcpu); /* @@ -5985,6 +5986,13 @@ static int __vmx_handle_exit(struct kvm_vcpu *vcpu, fastpath_t exit_fastpath) if (is_guest_mode(vcpu)) { /* + * PML is never enabled when running L2, bail immediately if a + * PML full exit occurs as something is horribly wrong. + */ + if (exit_reason.basic == EXIT_REASON_PML_FULL) + goto unexpected_vmexit; + + /* * The host physical addresses of some pages of guest memory * are loaded into the vmcs02 (e.g. vmcs12's Virtual APIC * Page). The CPU may write to these pages via their host |