[PATCH 3.14 38/51] arm64: KVM: allows discrimination of AArch32 sysreg access

Greg Kroah-Hartman
2015-05-15T23:33:07Z

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

commit 2072d29c46b73e39b3c6c56c6027af77086f45fd upstream.

The current handling of AArch32 trapping is slightly less than
perfect, as it is not possible (from a handler point of view)
to distinguish it from an AArch64 access, nor to tell a 32bit
from a 64bit access either.

Fix this by introducing two additional flags:
- is_aarch32: true if the access was made in AArch32 mode
- is_32bit: true if is_aarch32 == true and a MCR/MRC instruction
was used to perform the access (as opposed to MCRR/MRRC).

This allows a handler to cover all the possible conditions in which
a system register gets trapped.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Acked-by: Christoffer Dall <christoffer.dall@linaro.org>
Cc: Shannon Zhao <shannon.zhao@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
arch/arm64/kvm/sys_regs.c | 6 ++++++
arch/arm64/kvm/sys_regs.h | 2 ++
2 files changed, 8 insertions(+)

--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -437,6 +437,8 @@ int kvm_handle_cp15_64(struct kvm_vcpu *
u32 hsr = kvm_vcpu_get_hsr(vcpu);
int Rt2 = (hsr >> 10) & 0xf;

+ params.is_aarch32 = true;
+ params.is_32bit = false;
params.CRm = (hsr >> 1) & 0xf;
params.Rt = (hsr >> 5) & 0xf;
params.is_write = ((hsr & 1) == 0);
@@ -480,6 +482,8 @@ int kvm_handle_cp15_32(struct kvm_vcpu *
struct sys_reg_params params;
u32 hsr = kvm_vcpu_get_hsr(vcpu);

+ params.is_aarch32 = true;
+ params.is_32bit = true;
params.CRm = (hsr >> 1) & 0xf;
params.Rt = (hsr >> 5) & 0xf;
params.is_write = ((hsr & 1) == 0);
@@ -549,6 +553,8 @@ int kvm_handle_sys_reg(struct kvm_vcpu *
struct sys_reg_params params;
unsigned long esr = kvm_vcpu_get_hsr(vcpu);

+ params.is_aarch32 = false;
+ params.is_32bit = false;
params.Op0 = (esr >> 20) & 3;
params.Op1 = (esr >> 14) & 0x7;
params.CRn = (esr >> 10) & 0xf;
--- a/arch/arm64/kvm/sys_regs.h
+++ b/arch/arm64/kvm/sys_regs.h
@@ -30,6 +30,8 @@ struct sys_reg_params {
u8 Op2;
u8 Rt;
bool is_write;
+ bool is_aarch32;
+ bool is_32bit; /* Only valid if is_aarch32 is true */
};

struct sys_reg_desc {