diff options
| author | Pavel Fedin <p.fedin@samsung.com> | 2015-12-04 15:03:11 +0300 |
|---|---|---|
| committer | Marc Zyngier <marc.zyngier@arm.com> | 2015-12-04 16:29:37 +0000 |
| commit | bc45a516fa90b43b1898758d8b53b74c24b954e4 (patch) | |
| tree | ac99c251f2a2b292166fec8227f2438fb830150c /arch/arm64 | |
| parent | fbb4574ce9a37e15a9872860bf202f2be5bdf6c4 (diff) | |
arm64: KVM: Correctly handle zero register during MMIO
On ARM64 register index of 31 corresponds to both zero register and SP.
However, all memory access instructions, use ZR as transfer register. SP
is used only as a base register in indirect memory addressing, or by
register-register arithmetics, which cannot be trapped here.
Correct emulation is achieved by introducing new register accessor
functions, which can do special handling for reg_num == 31. These new
accessors intentionally do not rely on old vcpu_reg() on ARM64, because
it is to be removed. Since the affected code is shared by both ARM
flavours, implementations of these accessors are also added to ARM32 code.
This patch fixes setting MMIO register to a random value (actually SP)
instead of zero by something like:
*((volatile int *)reg) = 0;
compilers tend to generate "str wzr, [xx]" here
[Marc: Fixed 32bit splat]
Signed-off-by: Pavel Fedin <p.fedin@samsung.com>
Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Diffstat (limited to 'arch/arm64')
| -rw-r--r-- | arch/arm64/include/asm/kvm_emulate.h | 13 |
1 files changed, 13 insertions, 0 deletions
diff --git a/arch/arm64/include/asm/kvm_emulate.h b/arch/arm64/include/asm/kvm_emulate.h index 3ca894ecf699..5a182afab43b 100644 --- a/arch/arm64/include/asm/kvm_emulate.h +++ b/arch/arm64/include/asm/kvm_emulate.h @@ -109,6 +109,19 @@ static inline unsigned long *vcpu_reg(const struct kvm_vcpu *vcpu, u8 reg_num) return (unsigned long *)&vcpu_gp_regs(vcpu)->regs.regs[reg_num]; } +static inline unsigned long vcpu_get_reg(const struct kvm_vcpu *vcpu, + u8 reg_num) +{ + return (reg_num == 31) ? 0 : vcpu_gp_regs(vcpu)->regs.regs[reg_num]; +} + +static inline void vcpu_set_reg(struct kvm_vcpu *vcpu, u8 reg_num, + unsigned long val) +{ + if (reg_num != 31) + vcpu_gp_regs(vcpu)->regs.regs[reg_num] = val; +} + /* Get vcpu SPSR for current mode */ static inline unsigned long *vcpu_spsr(const struct kvm_vcpu *vcpu) { |