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KVM: arm64: Add vendor hypervisor firmware register
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Introduce the firmware register to hold the vendor specific
hypervisor service calls (owner value 6) 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 for KVM-vendor features along with
reading the UID, represented by bit-0, and Precision Time
Protocol (PTP), represented by bit-1.

Signed-off-by: Raghavendra Rao Ananta <rananta@google.com>
Reviewed-by: Gavin Shan <gshan@redhat.com>
[maz: tidy-up bitmap values]
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20220502233853.1233742-5-rananta@google.com
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Raghavendra Rao Ananta authored and Marc Zyngier committed May 3, 2022
1 parent 428fd67 commit b22216e
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Showing 3 changed files with 30 additions and 5 deletions.
2 changes: 2 additions & 0 deletions arch/arm64/include/asm/kvm_host.h
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Original file line number Diff line number Diff line change
Expand Up @@ -106,10 +106,12 @@ struct kvm_arch_memory_slot {
*
* @std_bmap: Bitmap of standard secure service calls
* @std_hyp_bmap: Bitmap of standard hypervisor service calls
* @vendor_hyp_bmap: Bitmap of vendor specific hypervisor service calls
*/
struct kvm_smccc_features {
unsigned long std_bmap;
unsigned long std_hyp_bmap;
unsigned long vendor_hyp_bmap;
};

struct kvm_arch {
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8 changes: 8 additions & 0 deletions arch/arm64/include/uapi/asm/kvm.h
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Original file line number Diff line number Diff line change
Expand Up @@ -352,6 +352,14 @@ enum {
KVM_REG_ARM_STD_HYP_BMAP_BIT_COUNT,
};

#define KVM_REG_ARM_VENDOR_HYP_BMAP KVM_REG_ARM_FW_FEAT_BMAP_REG(2)

enum {
KVM_REG_ARM_VENDOR_HYP_BIT_FUNC_FEAT = 0,
KVM_REG_ARM_VENDOR_HYP_BIT_PTP = 1,
KVM_REG_ARM_VENDOR_HYP_BMAP_BIT_COUNT,
};

/* Device Control API: ARM VGIC */
#define KVM_DEV_ARM_VGIC_GRP_ADDR 0
#define KVM_DEV_ARM_VGIC_GRP_DIST_REGS 1
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25 changes: 20 additions & 5 deletions arch/arm64/kvm/hypercalls.c
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Original file line number Diff line number Diff line change
Expand Up @@ -13,6 +13,8 @@
GENMASK(KVM_REG_ARM_STD_BMAP_BIT_COUNT - 1, 0)
#define KVM_ARM_SMCCC_STD_HYP_FEATURES \
GENMASK(KVM_REG_ARM_STD_HYP_BMAP_BIT_COUNT - 1, 0)
#define KVM_ARM_SMCCC_VENDOR_HYP_FEATURES \
GENMASK(KVM_REG_ARM_VENDOR_HYP_BMAP_BIT_COUNT - 1, 0)

static void kvm_ptp_get_time(struct kvm_vcpu *vcpu, u64 *val)
{
Expand Down Expand Up @@ -73,9 +75,6 @@ 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_VENDOR_HYP_CALL_UID_FUNC_ID:
case ARM_SMCCC_VENDOR_HYP_KVM_FEATURES_FUNC_ID:
case ARM_SMCCC_VENDOR_HYP_KVM_PTP_FUNC_ID:
return true;
default:
/* PSCI 0.2 and up is in the 0:0x1f range */
Expand Down Expand Up @@ -110,6 +109,13 @@ static bool kvm_hvc_call_allowed(struct kvm_vcpu *vcpu, u32 func_id)
case ARM_SMCCC_HV_PV_TIME_ST:
return test_bit(KVM_REG_ARM_STD_HYP_BIT_PV_TIME,
&smccc_feat->std_hyp_bmap);
case ARM_SMCCC_VENDOR_HYP_KVM_FEATURES_FUNC_ID:
case ARM_SMCCC_VENDOR_HYP_CALL_UID_FUNC_ID:
return test_bit(KVM_REG_ARM_VENDOR_HYP_BIT_FUNC_FEAT,
&smccc_feat->vendor_hyp_bmap);
case ARM_SMCCC_VENDOR_HYP_KVM_PTP_FUNC_ID:
return test_bit(KVM_REG_ARM_VENDOR_HYP_BIT_PTP,
&smccc_feat->vendor_hyp_bmap);
default:
return kvm_hvc_call_default_allowed(func_id);
}
Expand Down Expand Up @@ -202,8 +208,7 @@ int kvm_hvc_call_handler(struct kvm_vcpu *vcpu)
val[3] = ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_3;
break;
case ARM_SMCCC_VENDOR_HYP_KVM_FEATURES_FUNC_ID:
val[0] = BIT(ARM_SMCCC_KVM_FUNC_FEATURES);
val[0] |= BIT(ARM_SMCCC_KVM_FUNC_PTP);
val[0] = smccc_feat->vendor_hyp_bmap;
break;
case ARM_SMCCC_VENDOR_HYP_KVM_PTP_FUNC_ID:
kvm_ptp_get_time(vcpu, val);
Expand All @@ -230,6 +235,7 @@ static const u64 kvm_arm_fw_reg_ids[] = {
KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_3,
KVM_REG_ARM_STD_BMAP,
KVM_REG_ARM_STD_HYP_BMAP,
KVM_REG_ARM_VENDOR_HYP_BMAP,
};

void kvm_arm_init_hypercalls(struct kvm *kvm)
Expand All @@ -238,6 +244,7 @@ void kvm_arm_init_hypercalls(struct kvm *kvm)

smccc_feat->std_bmap = KVM_ARM_SMCCC_STD_FEATURES;
smccc_feat->std_hyp_bmap = KVM_ARM_SMCCC_STD_HYP_FEATURES;
smccc_feat->vendor_hyp_bmap = KVM_ARM_SMCCC_VENDOR_HYP_FEATURES;
}

int kvm_arm_get_fw_num_regs(struct kvm_vcpu *vcpu)
Expand Down Expand Up @@ -329,6 +336,9 @@ int kvm_arm_get_fw_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
case KVM_REG_ARM_STD_HYP_BMAP:
val = READ_ONCE(smccc_feat->std_hyp_bmap);
break;
case KVM_REG_ARM_VENDOR_HYP_BMAP:
val = READ_ONCE(smccc_feat->vendor_hyp_bmap);
break;
default:
return -ENOENT;
}
Expand All @@ -355,6 +365,10 @@ static int kvm_arm_set_fw_reg_bmap(struct kvm_vcpu *vcpu, u64 reg_id, u64 val)
fw_reg_bmap = &smccc_feat->std_hyp_bmap;
fw_reg_features = KVM_ARM_SMCCC_STD_HYP_FEATURES;
break;
case KVM_REG_ARM_VENDOR_HYP_BMAP:
fw_reg_bmap = &smccc_feat->vendor_hyp_bmap;
fw_reg_features = KVM_ARM_SMCCC_VENDOR_HYP_FEATURES;
break;
default:
return -ENOENT;
}
Expand Down Expand Up @@ -456,6 +470,7 @@ 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:
case KVM_REG_ARM_VENDOR_HYP_BMAP:
return kvm_arm_set_fw_reg_bmap(vcpu, reg->id, val);
default:
return -ENOENT;
Expand Down

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