diff options
| author | James Hogan <james.hogan@imgtec.com> | 2015-04-23 16:54:35 +0100 |
|---|---|---|
| committer | James Hogan <james.hogan@imgtec.com> | 2017-02-03 15:21:07 +0000 |
| commit | 6a97c775ff77fb7c54adc3f7944205ae66cb5475 (patch) | |
| tree | 7674922cbe9e70ed7ceb478e1b90c4c31ae8ab4e /arch/mips/include/asm | |
| parent | 122e51d47418f74a69a93bf02f5535d11ff75bf5 (diff) | |
KVM: MIPS: Use CP0_BadInstr[P] for emulation
When exiting from the guest, store the values of the CP0_BadInstr and
CP0_BadInstrP registers if they exist, which contain the encodings of
the instructions which caused the last synchronous exception.
When the instruction is needed for emulation, kvm_get_badinstr() and
kvm_get_badinstrp() are used instead of calling kvm_get_inst() directly,
to decide whether to read the saved CP0_BadInstr/CP0_BadInstrP registers
(if they exist), or read the instruction from memory (if not).
The use of these registers should be more robust than using
kvm_get_inst(), as it actually gives the instruction encoding seen by
the hardware rather than relying on user accessors after the fact, which
can be fooled by incoherent icache or a racing code modification. It
will also work with VZ, where the guest virtual memory isn't directly
accessible by the host with user accessors.
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
Diffstat (limited to 'arch/mips/include/asm')
| -rw-r--r-- | arch/mips/include/asm/kvm_host.h | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/arch/mips/include/asm/kvm_host.h b/arch/mips/include/asm/kvm_host.h index f296ebeda9e3..17c5e53ef3fa 100644 --- a/arch/mips/include/asm/kvm_host.h +++ b/arch/mips/include/asm/kvm_host.h @@ -280,6 +280,8 @@ struct kvm_vcpu_arch { unsigned long host_cp0_badvaddr; unsigned long host_cp0_epc; u32 host_cp0_cause; + u32 host_cp0_badinstr; + u32 host_cp0_badinstrp; /* GPRS */ unsigned long gprs[32]; @@ -641,6 +643,8 @@ void kvm_trap_emul_invalidate_gva(struct kvm_vcpu *vcpu, unsigned long addr, /* Emulation */ int kvm_get_inst(u32 *opc, struct kvm_vcpu *vcpu, u32 *out); enum emulation_result update_pc(struct kvm_vcpu *vcpu, u32 cause); +int kvm_get_badinstr(u32 *opc, struct kvm_vcpu *vcpu, u32 *out); +int kvm_get_badinstrp(u32 *opc, struct kvm_vcpu *vcpu, u32 *out); /** * kvm_is_ifetch_fault() - Find whether a TLBL exception is due to ifetch fault. |