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| author | Nadav Amit <namit@cs.technion.ac.il> | 2014-10-03 01:10:05 +0300 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2014-11-03 12:07:26 +0100 |
| commit | 16f8a6f9798ab9a1fd593b06b78925d02525ab81 (patch) | |
| tree | bacce115367ea875e4549d535fba9fbf429a2760 /arch/x86/include/asm/kvm_host.h | |
| parent | c49c759f7a68b70d2fed019760a66843b3df39b8 (diff) | |
| download | lwn-16f8a6f9798ab9a1fd593b06b78925d02525ab81.tar.gz lwn-16f8a6f9798ab9a1fd593b06b78925d02525ab81.zip | |
KVM: vmx: Unavailable DR4/5 is checked before CPL
If DR4/5 is accessed when it is unavailable (since CR4.DE is set), then #UD
should be generated even if CPL>0. This is according to Intel SDM Table 6-2:
"Priority Among Simultaneous Exceptions and Interrupts".
Note, that this may happen on the first DR access, even if the host does not
sets debug breakpoints. Obviously, it occurs when the host debugs the guest.
This patch moves the DR4/5 checks from __kvm_set_dr/_kvm_get_dr to handle_dr.
The emulator already checks DR4/5 availability in check_dr_read. Nested
virutalization related calls to kvm_set_dr/kvm_get_dr would not like to inject
exceptions to the guest.
As for SVM, the patch follows the previous logic as much as possible. Anyhow,
it appears the DR interception code might be buggy - even if the DR access
may cause an exception, the instruction is skipped.
Signed-off-by: Nadav Amit <namit@cs.technion.ac.il>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86/include/asm/kvm_host.h')
| -rw-r--r-- | arch/x86/include/asm/kvm_host.h | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index dd7cfc6de4a3..3ac807646911 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -895,6 +895,7 @@ int kvm_read_guest_page_mmu(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu, gfn_t gfn, void *data, int offset, int len, u32 access); bool kvm_require_cpl(struct kvm_vcpu *vcpu, int required_cpl); +bool kvm_require_dr(struct kvm_vcpu *vcpu, int dr); static inline int __kvm_irq_line_state(unsigned long *irq_state, int irq_source_id, int level) |