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KVM: arm64: Allow SMCCC_ARCH_WORKAROUND_3 to be discovered and migrated

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commit a5905d6af492ee6a4a2205f0d550b3f931b03d03 upstream.

KVM allows the guest to discover whether the ARCH_WORKAROUND SMCCC are
implemented, and to preserve that state during migration through its
firmware register interface.

Add the necessary boiler plate for SMCCC_ARCH_WORKAROUND_3.

Reviewed-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
[ kvm code moved to virt/kvm/arm. ]
Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
James Morse 2022-03-15 18:24:14 +00:00 committed by Greg Kroah-Hartman
parent 9013fd4bc9
commit fb65675f66
5 changed files with 54 additions and 3 deletions
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7
arch/arm/include/asm/kvm_host.h
View File

@ -15,6 +15,7 @@
#include <asm/kvm_asm.h>
#include <asm/kvm_mmio.h>
#include <asm/fpstate.h>
#include <asm/spectre.h>
#include <kvm/arm_arch_timer.h>
#define __KVM_HAVE_ARCH_INTC_INITIALIZED
@ -424,4 +425,10 @@ static inline bool kvm_arm_vcpu_is_finalized(struct kvm_vcpu *vcpu)
#define kvm_arm_vcpu_loaded(vcpu) (false)
static inline int kvm_arm_get_spectre_bhb_state(void)
{
/* 32bit guests don't need firmware for this */
return SPECTRE_VULNERABLE; /* aka SMCCC_RET_NOT_SUPPORTED */
}
#endif /* __ARM_KVM_HOST_H__ */

6
arch/arm/include/uapi/asm/kvm.h
View File

@ -227,6 +227,12 @@ struct kvm_vcpu_events {
#define KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_NOT_REQUIRED 3
#define KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_ENABLED (1U << 4)
#define KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_3 KVM_REG_ARM_FW_REG(3)
/* Higher values mean better protection. */
#define KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_3_NOT_AVAIL 0
#define KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_3_AVAIL 1
#define KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_3_NOT_REQUIRED 2
/* Device Control API: ARM VGIC */
#define KVM_DEV_ARM_VGIC_GRP_ADDR 0
#define KVM_DEV_ARM_VGIC_GRP_DIST_REGS 1

5
arch/arm64/include/asm/kvm_host.h
View File

@ -684,4 +684,9 @@ bool kvm_arm_vcpu_is_finalized(struct kvm_vcpu *vcpu);
#define kvm_arm_vcpu_loaded(vcpu) ((vcpu)->arch.sysregs_loaded_on_cpu)
static inline enum mitigation_state kvm_arm_get_spectre_bhb_state(void)
{
return arm64_get_spectre_bhb_state();
}
#endif /* __ARM64_KVM_HOST_H__ */

5
arch/arm64/include/uapi/asm/kvm.h
View File

@ -240,6 +240,11 @@ struct kvm_vcpu_events {
#define KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_NOT_REQUIRED 3
#define KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_ENABLED (1U << 4)
#define KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_3 KVM_REG_ARM_FW_REG(3)
#define KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_3_NOT_AVAIL 0
#define KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_3_AVAIL 1
#define KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_3_NOT_REQUIRED 2
/* SVE registers */
#define KVM_REG_ARM64_SVE (0x15 << KVM_REG_ARM_COPROC_SHIFT)

34
virt/kvm/arm/psci.c
View File

@ -426,6 +426,18 @@ int kvm_hvc_call_handler(struct kvm_vcpu *vcpu)
break;
}
break;
case ARM_SMCCC_ARCH_WORKAROUND_3:
switch (kvm_arm_get_spectre_bhb_state()) {
case SPECTRE_VULNERABLE:
break;
case SPECTRE_MITIGATED:
val = SMCCC_RET_SUCCESS;
break;
case SPECTRE_UNAFFECTED:
val = SMCCC_ARCH_WORKAROUND_RET_UNAFFECTED;
break;
}
break;
}
break;
default:
@ -438,7 +450,7 @@ int kvm_hvc_call_handler(struct kvm_vcpu *vcpu)
int kvm_arm_get_fw_num_regs(struct kvm_vcpu *vcpu)
{
return 3; /* PSCI version and two workaround registers */
return 4; /* PSCI version and three workaround registers */
}
int kvm_arm_copy_fw_reg_indices(struct kvm_vcpu *vcpu, u64 __user *uindices)
@ -452,6 +464,9 @@ int kvm_arm_copy_fw_reg_indices(struct kvm_vcpu *vcpu, u64 __user *uindices)
if (put_user(KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2, uindices++))
return -EFAULT;
if (put_user(KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_3, uindices++))
return -EFAULT;
return 0;
}
@ -486,9 +501,20 @@ static int get_kernel_wa_level(u64 regid)
return KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_NOT_REQUIRED;
case KVM_SSBD_UNKNOWN:
default:
return KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_UNKNOWN;
break;
}
}
return KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_UNKNOWN;
case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_3:
switch (kvm_arm_get_spectre_bhb_state()) {
case SPECTRE_VULNERABLE:
return KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_3_NOT_AVAIL;
case SPECTRE_MITIGATED:
return KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_3_AVAIL;
case SPECTRE_UNAFFECTED:
return KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_3_NOT_REQUIRED;
}
return KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_3_NOT_AVAIL;
}
return -EINVAL;
}
@ -503,6 +529,7 @@ int kvm_arm_get_fw_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
val = kvm_psci_version(vcpu, vcpu->kvm);
break;
case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_1:
case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_3:
val = get_kernel_wa_level(reg->id) & KVM_REG_FEATURE_LEVEL_MASK;
break;
case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2:
@ -555,6 +582,7 @@ int kvm_arm_set_fw_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
}
case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_1:
case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_3:
if (val & ~KVM_REG_FEATURE_LEVEL_MASK)
return -EINVAL;