[PATCH 28/59] KVM: arm64: nv: Respect the virtual HCR_EL2.NV1 bit setting

Marc Zyngier
2019-06-21T09:40:01Z

From: Jintack Lim <jintack@cs.columbia.edu>

Forward ELR_EL1, SPSR_EL1 and VBAR_EL1 traps to the virtual EL2 if the
virtual HCR_EL2.NV bit is set.

This is for recursive nested virtualization.

Signed-off-by: Jintack Lim <jintack@cs.columbia.edu>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
arch/arm64/include/asm/kvm_arm.h | 1 +
arch/arm64/kvm/sys_regs.c | 19 +++++++++++++++++--
2 files changed, 18 insertions(+), 2 deletions(-)

diff --git a/arch/arm64/include/asm/kvm_arm.h b/arch/arm64/include/asm/kvm_arm.h
index d21486274eeb..55f4525c112c 100644
--- a/arch/arm64/include/asm/kvm_arm.h
+++ b/arch/arm64/include/asm/kvm_arm.h
@@ -24,6 +24,7 @@

/* Hyp Configuration Register (HCR) bits */
#define HCR_FWB (UL(1) << 46)
+#define HCR_NV1 (UL(1) << 43)
#define HCR_NV (UL(1) << 42)
#define HCR_API (UL(1) << 41)
#define HCR_APK (UL(1) << 40)
diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index 0f74b9277a86..beadebcfc888 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -473,8 +473,10 @@ static bool access_vm_reg(struct kvm_vcpu *vcpu,
if (el12_reg(p) && forward_nv_traps(vcpu))
return false;

- if (!el12_reg(p) && forward_vm_traps(vcpu, p))
- return kvm_inject_nested_sync(vcpu, kvm_vcpu_get_hsr(vcpu));
+ if (!el12_reg(p) && forward_vm_traps(vcpu, p)) {
+ kvm_inject_nested_sync(vcpu, kvm_vcpu_get_hsr(vcpu));
+ return false;
+ }

BUG_ON(!vcpu_mode_el2(vcpu) && !p->is_write);

@@ -1643,6 +1645,13 @@ static bool access_sp_el1(struct kvm_vcpu *vcpu,
return true;
}

+
+/* This function is to support the recursive nested virtualization */
+static bool forward_nv1_traps(struct kvm_vcpu *vcpu, struct sys_reg_params *p)
+{
+ return forward_traps(vcpu, HCR_NV1);
+}
+
static bool access_elr(struct kvm_vcpu *vcpu,
struct sys_reg_params *p,
const struct sys_reg_desc *r)
@@ -1650,6 +1659,9 @@ static bool access_elr(struct kvm_vcpu *vcpu,
if (el12_reg(p) && forward_nv_traps(vcpu))
return false;

+ if (!el12_reg(p) && forward_nv1_traps(vcpu, p))
+ return false;
+
if (p->is_write)
vcpu->arch.ctxt.gp_regs.elr_el1 = p->regval;
else
@@ -1665,6 +1677,9 @@ static bool access_spsr(struct kvm_vcpu *vcpu,
if (el12_reg(p) && forward_nv_traps(vcpu))
return false;

+ if (!el12_reg(p) && forward_nv1_traps(vcpu, p))
+ return false;
+
if (p->is_write)
vcpu->arch.ctxt.gp_regs.spsr[KVM_SPSR_EL1] = p->regval;
else
--
2.20.1