[PATCH v7 3/9] KVM: arm64: Add standard hypervisor firmware register

Raghavendra Rao Ananta
2022-05-02T23:42:46Z

Introduce the firmware register to hold the standard hypervisor
service calls (owner value 5) as a bitmap. The bitmap represents
the features that'll be enabled for the guest, as configured by
the user-space. Currently, this includes support only for
Paravirtualized time, represented by bit-0.

Signed-off-by: Raghavendra Rao Ananta <rananta@google.com>
Reviewed-by: Gavin Shan <gshan@redhat.com>
---
arch/arm64/include/asm/kvm_host.h | 2 ++
arch/arm64/include/uapi/asm/kvm.h | 3 +++
arch/arm64/kvm/hypercalls.c | 21 ++++++++++++++++++---
include/kvm/arm_hypercalls.h | 2 ++
4 files changed, 25 insertions(+), 3 deletions(-)

diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index fef597af0beb..281dfcfd0a4e 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -105,9 +105,11 @@ struct kvm_arch_memory_slot {
* struct kvm_smccc_features: Descriptor of the hypercall services exposed to the guests
*
* @std_bmap: Bitmap of standard secure service calls
+ * @std_hyp_bmap: Bitmap of standard hypervisor service calls
*/
struct kvm_smccc_features {
unsigned long std_bmap;
+ unsigned long std_hyp_bmap;
};

struct kvm_arch {
diff --git a/arch/arm64/include/uapi/asm/kvm.h b/arch/arm64/include/uapi/asm/kvm.h
index 0b79d2dc6ffd..9eecc7ee8c14 100644
--- a/arch/arm64/include/uapi/asm/kvm.h
+++ b/arch/arm64/include/uapi/asm/kvm.h
@@ -341,6 +341,9 @@ struct kvm_arm_copy_mte_tags {
#define KVM_REG_ARM_STD_BMAP KVM_REG_ARM_FW_FEAT_BMAP_REG(0)
#define KVM_REG_ARM_STD_BIT_TRNG_V1_0 0

+#define KVM_REG_ARM_STD_HYP_BMAP KVM_REG_ARM_FW_FEAT_BMAP_REG(1)
+#define KVM_REG_ARM_STD_HYP_BIT_PV_TIME 0
+
/* Device Control API: ARM VGIC */
#define KVM_DEV_ARM_VGIC_GRP_ADDR 0
#define KVM_DEV_ARM_VGIC_GRP_DIST_REGS 1
diff --git a/arch/arm64/kvm/hypercalls.c b/arch/arm64/kvm/hypercalls.c
index 5c53fd1f5690..38440e0bd4b4 100644
--- a/arch/arm64/kvm/hypercalls.c
+++ b/arch/arm64/kvm/hypercalls.c
@@ -72,8 +72,6 @@ static bool kvm_hvc_call_default_allowed(u32 func_id)
*/
case ARM_SMCCC_VERSION_FUNC_ID:
case ARM_SMCCC_ARCH_FEATURES_FUNC_ID:
- case ARM_SMCCC_HV_PV_TIME_FEATURES:
- case ARM_SMCCC_HV_PV_TIME_ST:
case ARM_SMCCC_VENDOR_HYP_CALL_UID_FUNC_ID:
case ARM_SMCCC_VENDOR_HYP_KVM_FEATURES_FUNC_ID:
case ARM_SMCCC_VENDOR_HYP_KVM_PTP_FUNC_ID:
@@ -95,6 +93,10 @@ static bool kvm_hvc_call_allowed(struct kvm_vcpu *vcpu, u32 func_id)
case ARM_SMCCC_TRNG_RND64:
return kvm_arm_fw_reg_feat_enabled(&smccc_feat->std_bmap,
KVM_REG_ARM_STD_BIT_TRNG_V1_0);
+ case ARM_SMCCC_HV_PV_TIME_FEATURES:
+ case ARM_SMCCC_HV_PV_TIME_ST:
+ return kvm_arm_fw_reg_feat_enabled(&smccc_feat->std_hyp_bmap,
+ KVM_REG_ARM_STD_HYP_BIT_PV_TIME);
default:
return kvm_hvc_call_default_allowed(func_id);
}
@@ -102,6 +104,7 @@ static bool kvm_hvc_call_allowed(struct kvm_vcpu *vcpu, u32 func_id)

int kvm_hvc_call_handler(struct kvm_vcpu *vcpu)
{
+ struct kvm_smccc_features *smccc_feat = &vcpu->kvm->arch.smccc_feat;
u32 func_id = smccc_get_function(vcpu);
u64 val[4] = {SMCCC_RET_NOT_SUPPORTED};
u32 feature;
@@ -165,7 +168,9 @@ int kvm_hvc_call_handler(struct kvm_vcpu *vcpu)
}
break;
case ARM_SMCCC_HV_PV_TIME_FEATURES:
- val[0] = SMCCC_RET_SUCCESS;
+ if (kvm_arm_fw_reg_feat_enabled(&smccc_feat->std_hyp_bmap,
+ KVM_REG_ARM_STD_HYP_BIT_PV_TIME))
+ val[0] = SMCCC_RET_SUCCESS;
break;
}
break;
@@ -211,6 +216,7 @@ static const u64 kvm_arm_fw_reg_ids[] = {
KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2,
KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_3,
KVM_REG_ARM_STD_BMAP,
+ KVM_REG_ARM_STD_HYP_BMAP,
};

void kvm_arm_init_hypercalls(struct kvm *kvm)
@@ -218,6 +224,7 @@ void kvm_arm_init_hypercalls(struct kvm *kvm)
struct kvm_smccc_features *smccc_feat = &kvm->arch.smccc_feat;

smccc_feat->std_bmap = KVM_ARM_SMCCC_STD_FEATURES;
+ smccc_feat->std_hyp_bmap = KVM_ARM_SMCCC_STD_HYP_FEATURES;
}

int kvm_arm_get_fw_num_regs(struct kvm_vcpu *vcpu)
@@ -307,6 +314,9 @@ int kvm_arm_get_fw_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
case KVM_REG_ARM_STD_BMAP:
val = READ_ONCE(smccc_feat->std_bmap);
break;
+ case KVM_REG_ARM_STD_HYP_BMAP:
+ val = READ_ONCE(smccc_feat->std_hyp_bmap);
+ break;
default:
return -ENOENT;
}
@@ -329,6 +339,10 @@ static int kvm_arm_set_fw_reg_bmap(struct kvm_vcpu *vcpu, u64 reg_id, u64 val)
fw_reg_bmap = &smccc_feat->std_bmap;
fw_reg_features = KVM_ARM_SMCCC_STD_FEATURES;
break;
+ case KVM_REG_ARM_STD_HYP_BMAP:
+ fw_reg_bmap = &smccc_feat->std_hyp_bmap;
+ fw_reg_features = KVM_ARM_SMCCC_STD_HYP_FEATURES;
+ break;
default:
return -ENOENT;
}
@@ -442,6 +456,7 @@ int kvm_arm_set_fw_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)

return 0;
case KVM_REG_ARM_STD_BMAP:
+ case KVM_REG_ARM_STD_HYP_BMAP:
return kvm_arm_set_fw_reg_bmap(vcpu, reg->id, val);
default:
return -ENOENT;
diff --git a/include/kvm/arm_hypercalls.h b/include/kvm/arm_hypercalls.h
index c832e8411609..00f9f1b1dc16 100644
--- a/include/kvm/arm_hypercalls.h
+++ b/include/kvm/arm_hypercalls.h
@@ -8,8 +8,10 @@

/* Last valid bit of the bitmapped firmware registers */
#define KVM_REG_ARM_STD_BMAP_BIT_MAX 0
+#define KVM_REG_ARM_STD_HYP_BMAP_BIT_MAX 0

#define KVM_ARM_SMCCC_STD_FEATURES GENMASK(KVM_REG_ARM_STD_BMAP_BIT_MAX, 0)
+#define KVM_ARM_SMCCC_STD_HYP_FEATURES GENMASK(KVM_REG_ARM_STD_HYP_BMAP_BIT_MAX, 0)

int kvm_hvc_call_handler(struct kvm_vcpu *vcpu);

--
2.36.0.464.gb9c8b46e94-goog