ARM64: KVM: fix big endian issue in access_vm_reg for 32bit guest

Fix issue with 32bit guests running on top of BE KVM host.
Indexes of high and low words of 64bit cp15 register are
swapped in case of big endian code, since 64bit cp15 state is
restored or saved with double word write or read instruction.

Define helper macro to access low words of 64bit cp15 register.

Signed-off-by: Victor Kamensky <victor.kamensky@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
(cherry picked from commit f0a3eaff71b8bd5d5acfda1f0cf3eedf49755622)
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>

diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index 4ae9213aa99738f44a6458d0d26b3aa7da76869c..503c70661636fbbae0ae7fb749919fa971548749 100644 (file)
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -140,6 +140,12 @@ struct kvm_vcpu_arch {
 #define vcpu_sys_reg(v,r)      ((v)->arch.ctxt.sys_regs[(r)])
 #define vcpu_cp15(v,r)         ((v)->arch.ctxt.cp15[(r)])
 
+#ifdef CONFIG_CPU_BIG_ENDIAN
+#define vcpu_cp15_64_low(v,r) ((v)->arch.ctxt.cp15[((r) + 1)])
+#else
+#define vcpu_cp15_64_low(v,r) ((v)->arch.ctxt.cp15[((r) + 0)])
+#endif
+
 struct kvm_vm_stat {
        u32 remote_tlb_flush;
 };

diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index f0ceceffa95a6e542560c8dc38e4d68c1734b141..56288f31c12d9f8c642811fdbb6ebc70241132c7 100644 (file)
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -134,13 +134,11 @@ static bool access_vm_reg(struct kvm_vcpu *vcpu,
        BUG_ON(!p->is_write);
 
        val = *vcpu_reg(vcpu, p->Rt);
-       if (!p->is_aarch32) {
+       if (!p->is_aarch32 || !p->is_32bit)
                vcpu_sys_reg(vcpu, r->reg) = val;
-       } else {
-               vcpu_cp15(vcpu, r->reg) = val & 0xffffffffUL;
-               if (!p->is_32bit)
-                       vcpu_cp15(vcpu, r->reg + 1) = val >> 32;
-       }
+       else
+               vcpu_cp15_64_low(vcpu, r->reg) = val & 0xffffffffUL;
+
        return true;
 }