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-rw-r--r--arch/arm64/include/asm/kvm_host.h4
-rw-r--r--arch/arm64/kvm/hyp/exception.c6
2 files changed, 8 insertions, 2 deletions
diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index 3e41a880b062..cb7be34f6929 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -1149,6 +1149,8 @@ static inline bool __vcpu_read_sys_reg_from_cpu(int reg, u64 *val)
* System registers listed in the switch are not saved on every
* exit from the guest but are only saved on vcpu_put.
*
+ * SYSREGS_ON_CPU *MUST* be checked before using this helper.
+ *
* Note that MPIDR_EL1 for the guest is set by KVM via VMPIDR_EL2 but
* should never be listed below, because the guest cannot modify its
* own MPIDR_EL1 and MPIDR_EL1 is accessed for VCPU A from VCPU B's
@@ -1200,6 +1202,8 @@ static inline bool __vcpu_write_sys_reg_to_cpu(u64 val, int reg)
* System registers listed in the switch are not restored on every
* entry to the guest but are only restored on vcpu_load.
*
+ * SYSREGS_ON_CPU *MUST* be checked before using this helper.
+ *
* Note that MPIDR_EL1 for the guest is set by KVM via VMPIDR_EL2 but
* should never be listed below, because the MPIDR should only be set
* once, before running the VCPU, and never changed later.
diff --git a/arch/arm64/kvm/hyp/exception.c b/arch/arm64/kvm/hyp/exception.c
index 6a2a899a344e..9f5d837cc03f 100644
--- a/arch/arm64/kvm/hyp/exception.c
+++ b/arch/arm64/kvm/hyp/exception.c
@@ -26,7 +26,8 @@ static inline u64 __vcpu_read_sys_reg(const struct kvm_vcpu *vcpu, int reg)
if (unlikely(vcpu_has_nv(vcpu)))
return vcpu_read_sys_reg(vcpu, reg);
- else if (__vcpu_read_sys_reg_from_cpu(reg, &val))
+ else if (vcpu_get_flag(vcpu, SYSREGS_ON_CPU) &&
+ __vcpu_read_sys_reg_from_cpu(reg, &val))
return val;
return __vcpu_sys_reg(vcpu, reg);
@@ -36,7 +37,8 @@ static inline void __vcpu_write_sys_reg(struct kvm_vcpu *vcpu, u64 val, int reg)
{
if (unlikely(vcpu_has_nv(vcpu)))
vcpu_write_sys_reg(vcpu, val, reg);
- else if (!__vcpu_write_sys_reg_to_cpu(val, reg))
+ else if (!vcpu_get_flag(vcpu, SYSREGS_ON_CPU) ||
+ !__vcpu_write_sys_reg_to_cpu(val, reg))
__vcpu_assign_sys_reg(vcpu, reg, val);
}