[PATCH 3.16 102/134] arm64: KVM: Fix decoding of Rt/Rt2 when trapping AArch32 CP accesses

Ben Hutchings
2017-08-18T13:13:20Z

From: Marc Zyngier <marc.zyngier@arm.com>

commit c667186f1c01ca8970c785888868b7ffd74e51ee upstream.

Our 32bit CP14/15 handling inherited some of the ARMv7 code for handling
the trapped system registers, completely missing the fact that the
fields for Rt and Rt2 are now 5 bit wide, and not 4...

Let's fix it, and provide an accessor for the most common Rt case.

Reviewed-by: Christoffer Dall <cdall@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <cdall@linaro.org>
[bwh: Backported to 3.16:
- Use literal numbers in kvm_vcpu_sys_get_rt()
- Adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
arch/arm64/include/asm/kvm_emulate.h | 6 ++++++
arch/arm64/kvm/sys_regs.c | 8 ++++----
2 files changed, 10 insertions(+), 4 deletions(-)

--- a/arch/arm64/include/asm/kvm_emulate.h
+++ b/arch/arm64/include/asm/kvm_emulate.h
@@ -187,6 +187,12 @@ static inline u8 kvm_vcpu_trap_get_fault
return kvm_vcpu_get_hsr(vcpu) & ESR_EL2_FSC_TYPE;
}

+static inline int kvm_vcpu_sys_get_rt(struct kvm_vcpu *vcpu)
+{
+ u32 esr = kvm_vcpu_get_hsr(vcpu);
+ return (esr >> 5) & 0x1f;
+}
+
static inline unsigned long kvm_vcpu_get_mpidr(struct kvm_vcpu *vcpu)
{
return vcpu_sys_reg(vcpu, MPIDR_EL1);
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -504,12 +504,12 @@ int kvm_handle_cp15_64(struct kvm_vcpu *
{
struct sys_reg_params params;
u32 hsr = kvm_vcpu_get_hsr(vcpu);
- int Rt2 = (hsr >> 10) & 0xf;
+ int Rt2 = (hsr >> 10) & 0x1f;

params.is_aarch32 = true;
params.is_32bit = false;
params.CRm = (hsr >> 1) & 0xf;
- params.Rt = (hsr >> 5) & 0xf;
+ params.Rt = kvm_vcpu_sys_get_rt(vcpu);
params.is_write = ((hsr & 1) == 0);

params.Op0 = 0;
@@ -554,7 +554,7 @@ int kvm_handle_cp15_32(struct kvm_vcpu *
params.is_aarch32 = true;
params.is_32bit = true;
params.CRm = (hsr >> 1) & 0xf;
- params.Rt = (hsr >> 5) & 0xf;
+ params.Rt = kvm_vcpu_sys_get_rt(vcpu);
params.is_write = ((hsr & 1) == 0);
params.CRn = (hsr >> 10) & 0xf;
params.Op0 = 0;
@@ -629,7 +629,7 @@ int kvm_handle_sys_reg(struct kvm_vcpu *
params.CRn = (esr >> 10) & 0xf;
params.CRm = (esr >> 1) & 0xf;
params.Op2 = (esr >> 17) & 0x7;
- params.Rt = (esr >> 5) & 0x1f;
+ params.Rt = kvm_vcpu_sys_get_rt(vcpu);
params.is_write = !(esr & 1);

return emulate_sys_reg(vcpu, &params);