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[v4,11/12] KVM: arm64: BTI: Reset BTYPE when skipping emulated instructions

Message ID 20191211154206.46260-12-broonie@kernel.org
State New
Headers show
Series arm64: ARMv8.5-A: Branch Target Identification support | expand

Commit Message

Mark Brown Dec. 11, 2019, 3:42 p.m. UTC 
From: Dave Martin <Dave.Martin@arm.com>


Since normal execution of any non-branch instruction resets the
PSTATE BTYPE field to 0, so do the same thing when emulating a
trapped instruction.

Branches don't trap directly, so we should never need to assign a
non-zero value to BTYPE here.

Signed-off-by: Dave Martin <Dave.Martin@arm.com>

Signed-off-by: Mark Brown <broonie@kernel.org>

---
 arch/arm64/include/asm/kvm_emulate.h | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

-- 
2.20.1
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Patch

diff --git a/arch/arm64/include/asm/kvm_emulate.h b/arch/arm64/include/asm/kvm_emulate.h
index 5efe5ca8fecf..05fb1b4e0fa2 100644
--- a/arch/arm64/include/asm/kvm_emulate.h
+++ b/arch/arm64/include/asm/kvm_emulate.h
@@ -470,10 +470,12 @@  static inline unsigned long vcpu_data_host_to_guest(struct kvm_vcpu *vcpu,
 
 static inline void kvm_skip_instr(struct kvm_vcpu *vcpu, bool is_wide_instr)
 {
-	if (vcpu_mode_is_32bit(vcpu))
+	if (vcpu_mode_is_32bit(vcpu)) {
 		kvm_skip_instr32(vcpu, is_wide_instr);
-	else
+	} else {
 		*vcpu_pc(vcpu) += 4;
+		*vcpu_cpsr(vcpu) &= ~PSR_BTYPE_MASK;
+	}
 
 	/* advance the singlestep state machine */
 	*vcpu_cpsr(vcpu) &= ~DBG_SPSR_SS;