From: Christoffer Dall <christoffer.dall@xxxxxxx>
When a guest hypervisor running virtual EL2 in EL1 executes an ERET
instruction, we will have set HCR_EL2.NV which traps ERET to EL2, so
that we can emulate the exception return in software.
Signed-off-by: Christoffer Dall <christoffer.dall@xxxxxxx>
Signed-off-by: Marc Zyngier <maz@xxxxxxxxxx>
---
arch/arm64/include/asm/esr.h | 5 +++++
arch/arm64/include/asm/kvm_arm.h | 2 +-
arch/arm64/kvm/handle_exit.c | 10 ++++++++++
3 files changed, 16 insertions(+), 1 deletion(-)
diff --git a/arch/arm64/include/asm/esr.h b/arch/arm64/include/asm/esr.h
index cb29253ae86b..b15921dc889a 100644
--- a/arch/arm64/include/asm/esr.h
+++ b/arch/arm64/include/asm/esr.h
@@ -249,6 +249,11 @@
(((e) & ESR_ELx_SYS64_ISS_OP2_MASK) >> \
ESR_ELx_SYS64_ISS_OP2_SHIFT))
+/* ISS field definitions for ERET/ERETAA/ERETAB trapping */
+
+#define ESR_ELx_ERET_ISS_ERET_ERETAx 0x2
+#define ESR_ELx_ERET_ISS_ERETA_ERATAB 0x1
+
/*
* ISS field definitions for floating-point exception traps
* (FP_EXC_32/FP_EXC_64).
diff --git a/arch/arm64/include/asm/kvm_arm.h b/arch/arm64/include/asm/kvm_arm.h
index 93469ac81fef..084844ec0b06 100644
--- a/arch/arm64/include/asm/kvm_arm.h
+++ b/arch/arm64/include/asm/kvm_arm.h
@@ -322,7 +322,7 @@
ECN(SP_ALIGN), ECN(FP_EXC32), ECN(FP_EXC64), ECN(SERROR), \
ECN(BREAKPT_LOW), ECN(BREAKPT_CUR), ECN(SOFTSTP_LOW), \
ECN(SOFTSTP_CUR), ECN(WATCHPT_LOW), ECN(WATCHPT_CUR), \
- ECN(BKPT32), ECN(VECTOR32), ECN(BRK64)
+ ECN(BKPT32), ECN(VECTOR32), ECN(BRK64), ECN(ERET)
#define CPACR_EL1_FPEN (3 << 20)
#define CPACR_EL1_TTA (1 << 28)
diff --git a/arch/arm64/kvm/handle_exit.c b/arch/arm64/kvm/handle_exit.c
index be5acf72c81e..c3398e6ebbbe 100644
--- a/arch/arm64/kvm/handle_exit.c
+++ b/arch/arm64/kvm/handle_exit.c
@@ -210,6 +210,15 @@ static int kvm_handle_ptrauth(struct kvm_vcpu *vcpu, struct kvm_run *run)
return 1;
}
+static int kvm_handle_eret(struct kvm_vcpu *vcpu, struct kvm_run *run)
+{
+ if (kvm_vcpu_get_hsr(vcpu) & ESR_ELx_ERET_ISS_ERET_ERETAx)
+ return kvm_handle_ptrauth(vcpu, run);
+
+ kvm_emulate_nested_eret(vcpu);
+ return 1;
+}
+
static exit_handle_fn arm_exit_handlers[] = {
[0 ... ESR_ELx_EC_MAX] = kvm_handle_unknown_ec,
[ESR_ELx_EC_WFx] = kvm_handle_wfx,
@@ -224,6 +233,7 @@ static exit_handle_fn arm_exit_handlers[] = {
[ESR_ELx_EC_SMC64] = handle_smc,
[ESR_ELx_EC_SYS64] = kvm_handle_sys_reg,
[ESR_ELx_EC_SVE] = handle_sve,
+ [ESR_ELx_EC_ERET] = kvm_handle_eret,
[ESR_ELx_EC_IABT_LOW] = kvm_handle_guest_abort,
[ESR_ELx_EC_DABT_LOW] = kvm_handle_guest_abort,
[ESR_ELx_EC_SOFTSTP_LOW]= kvm_handle_guest_debug,
--
2.20.1
