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| author | Sean Christopherson <sean.j.christopherson@intel.com> | 2020-04-16 03:07:39 +0300 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2020-04-21 16:13:09 +0300 |
| commit | b8d295f96b6c9745d7eebee622690e0e835c63af (patch) | |
| tree | 1ea185121d41d5ec121422bf758397870f05b554 /arch/x86/kvm/vmx/vmcs12.c | |
| parent | c36b71503a2268206ebeda6697094ffb4e7e94c2 (diff) | |
| download | linux-b8d295f96b6c9745d7eebee622690e0e835c63af.tar.xz | |
KVM: nVMX: Remove non-functional "support" for CR3 target values
Remove all references to cr3_target_value[0-3] and replace the fields
in vmcs12 with "dead_space" to preserve the vmcs12 layout. KVM doesn't
support emulating CR3-target values, despite a variety of code that
implies otherwise, as KVM unconditionally reports '0' for the number of
supported CR3-target values.
This technically fixes a bug where KVM would incorrectly allow VMREAD
and VMWRITE to nonexistent fields, i.e. cr3_target_value[0-3]. Per
Intel's SDM, the number of supported CR3-target values reported in
VMX_MISC also enumerates the existence of the associated VMCS fields:
If a future implementation supports more than 4 CR3-target values, they
will be encoded consecutively following the 4 encodings given here.
Alternatively, the "bug" could be fixed by actually advertisting support
for 4 CR3-target values, but that'd likely just enable kvm-unit-tests
given that no one has complained about lack of support for going on ten
years, e.g. KVM, Xen and HyperV don't use CR3-target values.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Message-Id: <20200416000739.9012-1-sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86/kvm/vmx/vmcs12.c')
| -rw-r--r-- | arch/x86/kvm/vmx/vmcs12.c | 4 |
1 files changed, 0 insertions, 4 deletions
diff --git a/arch/x86/kvm/vmx/vmcs12.c b/arch/x86/kvm/vmx/vmcs12.c index 53dfb401316d..c8e51c004f78 100644 --- a/arch/x86/kvm/vmx/vmcs12.c +++ b/arch/x86/kvm/vmx/vmcs12.c @@ -115,10 +115,6 @@ const unsigned short vmcs_field_to_offset_table[] = { FIELD(CR4_GUEST_HOST_MASK, cr4_guest_host_mask), FIELD(CR0_READ_SHADOW, cr0_read_shadow), FIELD(CR4_READ_SHADOW, cr4_read_shadow), - FIELD(CR3_TARGET_VALUE0, cr3_target_value0), - FIELD(CR3_TARGET_VALUE1, cr3_target_value1), - FIELD(CR3_TARGET_VALUE2, cr3_target_value2), - FIELD(CR3_TARGET_VALUE3, cr3_target_value3), FIELD(EXIT_QUALIFICATION, exit_qualification), FIELD(GUEST_LINEAR_ADDRESS, guest_linear_address), FIELD(GUEST_CR0, guest_cr0), |