[RFC 08/55] KVM: arm64: Set virtual EL2 context depending on the guest exception level

Jintack Lim
2017-01-09T06:24:04Z

From: Christoffer Dall <christoffer.dall@linaro.org>

Set up virutal EL2 context to hardware if the guest exception level is
EL2.

Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Jintack Lim <jintack@cs.columbia.edu>
---
arch/arm64/kvm/context.c | 32 ++++++++++++++++++++++++++------
1 file changed, 26 insertions(+), 6 deletions(-)

diff --git a/arch/arm64/kvm/context.c b/arch/arm64/kvm/context.c
index 320afc6..acb4b1e 100644
--- a/arch/arm64/kvm/context.c
+++ b/arch/arm64/kvm/context.c
@@ -25,10 +25,25 @@
void kvm_arm_setup_shadow_state(struct kvm_vcpu *vcpu)
{
struct kvm_cpu_context *ctxt = &vcpu->arch.ctxt;
+ if (unlikely(vcpu_mode_el2(vcpu))) {
+ ctxt->hw_pstate = *vcpu_cpsr(vcpu) & ~PSR_MODE_MASK;

- ctxt->hw_pstate = *vcpu_cpsr(vcpu);
- ctxt->hw_sys_regs = ctxt->sys_regs;
- ctxt->hw_sp_el1 = ctxt->gp_regs.sp_el1;
+ /*
+ * We emulate virtual EL2 mode in hardware EL1 mode using the
+ * same stack pointer mode as the guest expects.
+ */
+ if ((*vcpu_cpsr(vcpu) & PSR_MODE_MASK) == PSR_MODE_EL2h)
+ ctxt->hw_pstate |= PSR_MODE_EL1h;
+ else
+ ctxt->hw_pstate |= PSR_MODE_EL1t;
+
+ ctxt->hw_sys_regs = ctxt->shadow_sys_regs;
+ ctxt->hw_sp_el1 = ctxt->el2_regs[SP_EL2];
+ } else {
+ ctxt->hw_pstate = *vcpu_cpsr(vcpu);
+ ctxt->hw_sys_regs = ctxt->sys_regs;
+ ctxt->hw_sp_el1 = ctxt->gp_regs.sp_el1;
+ }
}

/**
@@ -38,9 +53,14 @@ void kvm_arm_setup_shadow_state(struct kvm_vcpu *vcpu)
void kvm_arm_restore_shadow_state(struct kvm_vcpu *vcpu)
{
struct kvm_cpu_context *ctxt = &vcpu->arch.ctxt;
-
- *vcpu_cpsr(vcpu) = ctxt->hw_pstate;
- ctxt->gp_regs.sp_el1 = ctxt->hw_sp_el1;
+ if (unlikely(vcpu_mode_el2(vcpu))) {
+ *vcpu_cpsr(vcpu) &= PSR_MODE_MASK;
+ *vcpu_cpsr(vcpu) |= ctxt->hw_pstate & ~PSR_MODE_MASK;
+ ctxt->el2_regs[SP_EL2] = ctxt->hw_sp_el1;
+ } else {
+ *vcpu_cpsr(vcpu) = ctxt->hw_pstate;
+ ctxt->gp_regs.sp_el1 = ctxt->hw_sp_el1;
+ }
}

void kvm_arm_init_cpu_context(kvm_cpu_context_t *cpu_ctxt)
--
1.9.1