[RFC 03/55] KVM: arm64: Add KVM nesting feature

From: Jintack Lim
Date: Mon Jan 09 2017 - 01:40:29 EST


From: Christoffer Dall <christoffer.dall@xxxxxxxxxx>

Set the initial exception level of the guest to EL2 if nested
virtualization feature is enabled.

Signed-off-by: Christoffer Dall <christoffer.dall@xxxxxxxxxx>
Signed-off-by: Jintack Lim <jintack@xxxxxxxxxxxxxxx>
---
arch/arm64/include/asm/kvm_host.h | 2 +-
arch/arm64/include/uapi/asm/kvm.h | 1 +
arch/arm64/kvm/reset.c | 8 ++++++++
3 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index e505038..c0c8b02 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -41,7 +41,7 @@

#define KVM_MAX_VCPUS VGIC_V3_MAX_CPUS

-#define KVM_VCPU_MAX_FEATURES 4
+#define KVM_VCPU_MAX_FEATURES 5

#define KVM_REQ_VCPU_EXIT 8

diff --git a/arch/arm64/include/uapi/asm/kvm.h b/arch/arm64/include/uapi/asm/kvm.h
index 3051f86..78117bf 100644
--- a/arch/arm64/include/uapi/asm/kvm.h
+++ b/arch/arm64/include/uapi/asm/kvm.h
@@ -97,6 +97,7 @@ struct kvm_regs {
#define KVM_ARM_VCPU_EL1_32BIT 1 /* CPU running a 32bit VM */
#define KVM_ARM_VCPU_PSCI_0_2 2 /* CPU uses PSCI v0.2 */
#define KVM_ARM_VCPU_PMU_V3 3 /* Support guest PMUv3 */
+#define KVM_ARM_VCPU_NESTED_VIRT 4 /* Support nested virtual EL2 */

struct kvm_vcpu_init {
__u32 target;
diff --git a/arch/arm64/kvm/reset.c b/arch/arm64/kvm/reset.c
index 74322c2..e6b0b20 100644
--- a/arch/arm64/kvm/reset.c
+++ b/arch/arm64/kvm/reset.c
@@ -41,6 +41,11 @@
PSR_F_BIT | PSR_D_BIT),
};

+static const struct kvm_regs default_regs_reset_el2 = {
+ .regs.pstate = (PSR_MODE_EL2h | PSR_A_BIT | PSR_I_BIT |
+ PSR_F_BIT | PSR_D_BIT),
+};
+
static const struct kvm_regs default_regs_reset32 = {
.regs.pstate = (COMPAT_PSR_MODE_SVC | COMPAT_PSR_A_BIT |
COMPAT_PSR_I_BIT | COMPAT_PSR_F_BIT),
@@ -124,6 +129,9 @@ int kvm_reset_vcpu(struct kvm_vcpu *vcpu)
if (!cpu_has_32bit_el1())
return -EINVAL;
cpu_reset = &default_regs_reset32;
+ } else if (test_bit(KVM_ARM_VCPU_NESTED_VIRT,
+ vcpu->arch.features)) {
+ cpu_reset = &default_regs_reset_el2;
} else {
cpu_reset = &default_regs_reset;
}
--
1.9.1