AcoSail/kernel_optimize_test
8
0
Fork 0
forked from luck/tmp_suning_uos_patched
Code Pull Requests Activity

arm64: KVM: Correctly handle zero register during MMIO

Browse Source 
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>
This commit is contained in:
Pavel Fedin 2015-12-04 15:03:11 +03:00 committed by Marc Zyngier
parent fbb4574ce9
commit bc45a516fa
3 changed files with 28 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

12
arch/arm/include/asm/kvm_emulate.h
View File

@ -28,6 +28,18 @@
unsigned long *vcpu_reg(struct kvm_vcpu *vcpu, u8 reg_num);
unsigned long *vcpu_spsr(struct kvm_vcpu *vcpu);
static inline unsigned long vcpu_get_reg(struct kvm_vcpu *vcpu,
u8 reg_num)
{
return *vcpu_reg(vcpu, reg_num);
}
static inline void vcpu_set_reg(struct kvm_vcpu *vcpu, u8 reg_num,
unsigned long val)
{
*vcpu_reg(vcpu, reg_num) = val;
}
bool kvm_condition_valid(struct kvm_vcpu *vcpu);
void kvm_skip_instr(struct kvm_vcpu *vcpu, bool is_wide_instr);
void kvm_inject_undefined(struct kvm_vcpu *vcpu);

5
arch/arm/kvm/mmio.c
View File

@ -115,7 +115,7 @@ int kvm_handle_mmio_return(struct kvm_vcpu *vcpu, struct kvm_run *run)
trace_kvm_mmio(KVM_TRACE_MMIO_READ, len, run->mmio.phys_addr,
data);
data = vcpu_data_host_to_guest(vcpu, data, len);
*vcpu_reg(vcpu, vcpu->arch.mmio_decode.rt) = data;
vcpu_set_reg(vcpu, vcpu->arch.mmio_decode.rt, data);
}
return 0;
@ -186,7 +186,8 @@ int io_mem_abort(struct kvm_vcpu *vcpu, struct kvm_run *run,
rt = vcpu->arch.mmio_decode.rt;
if (is_write) {
data = vcpu_data_guest_to_host(vcpu, *vcpu_reg(vcpu, rt), len);
data = vcpu_data_guest_to_host(vcpu, vcpu_get_reg(vcpu, rt),
len);
trace_kvm_mmio(KVM_TRACE_MMIO_WRITE, len, fault_ipa, data);
mmio_write_buf(data_buf, len, data);

13
arch/arm64/include/asm/kvm_emulate.h
View File

@ -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)
{