[PATCH v7 1/9] KVM: arm64: Factor out firmware register handling from psci.c

Raghavendra Rao Ananta
2022-05-02T23:40:36Z

Common hypercall firmware register handing is currently employed
by psci.c. Since the upcoming patches add more of these registers,
it's better to move the generic handling to hypercall.c for a
cleaner presentation.

While we are at it, collect all the firmware registers under
fw_reg_ids[] to help implement kvm_arm_get_fw_num_regs() and
kvm_arm_copy_fw_reg_indices() in a generic way. Also, define
KVM_REG_FEATURE_LEVEL_MASK using a GENMASK instead.

No functional change intended.

Signed-off-by: Raghavendra Rao Ananta <rananta@google.com>
Reviewed-by: Oliver Upton <oupton@google.com>
Reviewed-by: Gavin Shan <gshan@redhat.com>
---
arch/arm64/kvm/guest.c | 2 +-
arch/arm64/kvm/hypercalls.c | 185 +++++++++++++++++++++++++++++++++++
arch/arm64/kvm/psci.c | 183 ----------------------------------
include/kvm/arm_hypercalls.h | 7 ++
include/kvm/arm_psci.h | 7 --
5 files changed, 193 insertions(+), 191 deletions(-)

diff --git a/arch/arm64/kvm/guest.c b/arch/arm64/kvm/guest.c
index 7e15b03fbdf8..0d5cca56cbda 100644
--- a/arch/arm64/kvm/guest.c
+++ b/arch/arm64/kvm/guest.c
@@ -18,7 +18,7 @@
#include <linux/string.h>
#include <linux/vmalloc.h>
#include <linux/fs.h>
-#include <kvm/arm_psci.h>
+#include <kvm/arm_hypercalls.h>
#include <asm/cputype.h>
#include <linux/uaccess.h>
#include <asm/fpsimd.h>
diff --git a/arch/arm64/kvm/hypercalls.c b/arch/arm64/kvm/hypercalls.c
index 202b8c455724..fa6d9378d8e7 100644
--- a/arch/arm64/kvm/hypercalls.c
+++ b/arch/arm64/kvm/hypercalls.c
@@ -158,3 +158,188 @@ int kvm_hvc_call_handler(struct kvm_vcpu *vcpu)
smccc_set_retval(vcpu, val[0], val[1], val[2], val[3]);
return 1;
}
+
+static const u64 kvm_arm_fw_reg_ids[] = {
+ KVM_REG_ARM_PSCI_VERSION,
+ KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_1,
+ KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2,
+ KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_3,
+};
+
+int kvm_arm_get_fw_num_regs(struct kvm_vcpu *vcpu)
+{
+ return ARRAY_SIZE(kvm_arm_fw_reg_ids);
+}
+
+int kvm_arm_copy_fw_reg_indices(struct kvm_vcpu *vcpu, u64 __user *uindices)
+{
+ int i;
+
+ for (i = 0; i < ARRAY_SIZE(kvm_arm_fw_reg_ids); i++) {
+ if (put_user(kvm_arm_fw_reg_ids[i], uindices++))
+ return -EFAULT;
+ }
+
+ return 0;
+}
+
+#define KVM_REG_FEATURE_LEVEL_WIDTH 4
+#define KVM_REG_FEATURE_LEVEL_MASK GENMASK(KVM_REG_FEATURE_LEVEL_WIDTH, 0)
+
+/*
+ * Convert the workaround level into an easy-to-compare number, where higher
+ * values mean better protection.
+ */
+static int get_kernel_wa_level(u64 regid)
+{
+ switch (regid) {
+ case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_1:
+ switch (arm64_get_spectre_v2_state()) {
+ case SPECTRE_VULNERABLE:
+ return KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_1_NOT_AVAIL;
+ case SPECTRE_MITIGATED:
+ return KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_1_AVAIL;
+ case SPECTRE_UNAFFECTED:
+ return KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_1_NOT_REQUIRED;
+ }
+ return KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_1_NOT_AVAIL;
+ case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2:
+ switch (arm64_get_spectre_v4_state()) {
+ case SPECTRE_MITIGATED:
+ /*
+ * As for the hypercall discovery, we pretend we
+ * don't have any FW mitigation if SSBS is there at
+ * all times.
+ */
+ if (cpus_have_final_cap(ARM64_SSBS))
+ return KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_NOT_AVAIL;
+ fallthrough;
+ case SPECTRE_UNAFFECTED:
+ return KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_NOT_REQUIRED;
+ case SPECTRE_VULNERABLE:
+ return KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_NOT_AVAIL;
+ }
+ break;
+ case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_3:
+ switch (arm64_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;
+}
+
+int kvm_arm_get_fw_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
+{
+ void __user *uaddr = (void __user *)(long)reg->addr;
+ u64 val;
+
+ switch (reg->id) {
+ case KVM_REG_ARM_PSCI_VERSION:
+ val = kvm_psci_version(vcpu);
+ break;
+ case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_1:
+ case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2:
+ case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_3:
+ val = get_kernel_wa_level(reg->id) & KVM_REG_FEATURE_LEVEL_MASK;
+ break;
+ default:
+ return -ENOENT;
+ }
+
+ if (copy_to_user(uaddr, &val, KVM_REG_SIZE(reg->id)))
+ return -EFAULT;
+
+ return 0;
+}
+
+int kvm_arm_set_fw_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
+{
+ void __user *uaddr = (void __user *)(long)reg->addr;
+ u64 val;
+ int wa_level;
+
+ if (copy_from_user(&val, uaddr, KVM_REG_SIZE(reg->id)))
+ return -EFAULT;
+
+ switch (reg->id) {
+ case KVM_REG_ARM_PSCI_VERSION:
+ {
+ bool wants_02;
+
+ wants_02 = test_bit(KVM_ARM_VCPU_PSCI_0_2, vcpu->arch.features);
+
+ switch (val) {
+ case KVM_ARM_PSCI_0_1:
+ if (wants_02)
+ return -EINVAL;
+ vcpu->kvm->arch.psci_version = val;
+ return 0;
+ case KVM_ARM_PSCI_0_2:
+ case KVM_ARM_PSCI_1_0:
+ case KVM_ARM_PSCI_1_1:
+ if (!wants_02)
+ return -EINVAL;
+ vcpu->kvm->arch.psci_version = val;
+ return 0;
+ }
+ break;
+ }
+
+ 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;
+
+ if (get_kernel_wa_level(reg->id) < val)
+ return -EINVAL;
+
+ return 0;
+
+ case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2:
+ if (val & ~(KVM_REG_FEATURE_LEVEL_MASK |
+ KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_ENABLED))
+ return -EINVAL;
+
+ /* The enabled bit must not be set unless the level is AVAIL. */
+ if ((val & KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_ENABLED) &&
+ (val & KVM_REG_FEATURE_LEVEL_MASK) != KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_AVAIL)
+ return -EINVAL;
+
+ /*
+ * Map all the possible incoming states to the only two we
+ * really want to deal with.
+ */
+ switch (val & KVM_REG_FEATURE_LEVEL_MASK) {
+ case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_NOT_AVAIL:
+ case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_UNKNOWN:
+ wa_level = KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_NOT_AVAIL;
+ break;
+ case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_AVAIL:
+ case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_NOT_REQUIRED:
+ wa_level = KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_NOT_REQUIRED;
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ /*
+ * We can deal with NOT_AVAIL on NOT_REQUIRED, but not the
+ * other way around.
+ */
+ if (get_kernel_wa_level(reg->id) < wa_level)
+ return -EINVAL;
+
+ return 0;
+ default:
+ return -ENOENT;
+ }
+
+ return -EINVAL;
+}
diff --git a/arch/arm64/kvm/psci.c b/arch/arm64/kvm/psci.c
index 708d80e8e60d..4bb76eb09248 100644
--- a/arch/arm64/kvm/psci.c
+++ b/arch/arm64/kvm/psci.c
@@ -437,186 +437,3 @@ int kvm_psci_call(struct kvm_vcpu *vcpu)
return -EINVAL;
}
}
-
-int kvm_arm_get_fw_num_regs(struct kvm_vcpu *vcpu)
-{
- return 4; /* PSCI version and three workaround registers */
-}
-
-int kvm_arm_copy_fw_reg_indices(struct kvm_vcpu *vcpu, u64 __user *uindices)
-{
- if (put_user(KVM_REG_ARM_PSCI_VERSION, uindices++))
- return -EFAULT;
-
- if (put_user(KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_1, uindices++))
- return -EFAULT;
-
- 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;
-}
-
-#define KVM_REG_FEATURE_LEVEL_WIDTH 4
-#define KVM_REG_FEATURE_LEVEL_MASK (BIT(KVM_REG_FEATURE_LEVEL_WIDTH) - 1)
-
-/*
- * Convert the workaround level into an easy-to-compare number, where higher
- * values mean better protection.
- */
-static int get_kernel_wa_level(u64 regid)
-{
- switch (regid) {
- case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_1:
- switch (arm64_get_spectre_v2_state()) {
- case SPECTRE_VULNERABLE:
- return KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_1_NOT_AVAIL;
- case SPECTRE_MITIGATED:
- return KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_1_AVAIL;
- case SPECTRE_UNAFFECTED:
- return KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_1_NOT_REQUIRED;
- }
- return KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_1_NOT_AVAIL;
- case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2:
- switch (arm64_get_spectre_v4_state()) {
- case SPECTRE_MITIGATED:
- /*
- * As for the hypercall discovery, we pretend we
- * don't have any FW mitigation if SSBS is there at
- * all times.
- */
- if (cpus_have_final_cap(ARM64_SSBS))
- return KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_NOT_AVAIL;
- fallthrough;
- case SPECTRE_UNAFFECTED:
- return KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_NOT_REQUIRED;
- case SPECTRE_VULNERABLE:
- return KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_NOT_AVAIL;
- }
- break;
- case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_3:
- switch (arm64_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;
-}
-
-int kvm_arm_get_fw_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
-{
- void __user *uaddr = (void __user *)(long)reg->addr;
- u64 val;
-
- switch (reg->id) {
- case KVM_REG_ARM_PSCI_VERSION:
- val = kvm_psci_version(vcpu);
- break;
- case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_1:
- case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2:
- case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_3:
- val = get_kernel_wa_level(reg->id) & KVM_REG_FEATURE_LEVEL_MASK;
- break;
- default:
- return -ENOENT;
- }
-
- if (copy_to_user(uaddr, &val, KVM_REG_SIZE(reg->id)))
- return -EFAULT;
-
- return 0;
-}
-
-int kvm_arm_set_fw_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
-{
- void __user *uaddr = (void __user *)(long)reg->addr;
- u64 val;
- int wa_level;
-
- if (copy_from_user(&val, uaddr, KVM_REG_SIZE(reg->id)))
- return -EFAULT;
-
- switch (reg->id) {
- case KVM_REG_ARM_PSCI_VERSION:
- {
- bool wants_02;
-
- wants_02 = test_bit(KVM_ARM_VCPU_PSCI_0_2, vcpu->arch.features);
-
- switch (val) {
- case KVM_ARM_PSCI_0_1:
- if (wants_02)
- return -EINVAL;
- vcpu->kvm->arch.psci_version = val;
- return 0;
- case KVM_ARM_PSCI_0_2:
- case KVM_ARM_PSCI_1_0:
- case KVM_ARM_PSCI_1_1:
- if (!wants_02)
- return -EINVAL;
- vcpu->kvm->arch.psci_version = val;
- return 0;
- }
- break;
- }
-
- 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;
-
- if (get_kernel_wa_level(reg->id) < val)
- return -EINVAL;
-
- return 0;
-
- case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2:
- if (val & ~(KVM_REG_FEATURE_LEVEL_MASK |
- KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_ENABLED))
- return -EINVAL;
-
- /* The enabled bit must not be set unless the level is AVAIL. */
- if ((val & KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_ENABLED) &&
- (val & KVM_REG_FEATURE_LEVEL_MASK) != KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_AVAIL)
- return -EINVAL;
-
- /*
- * Map all the possible incoming states to the only two we
- * really want to deal with.
- */
- switch (val & KVM_REG_FEATURE_LEVEL_MASK) {
- case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_NOT_AVAIL:
- case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_UNKNOWN:
- wa_level = KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_NOT_AVAIL;
- break;
- case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_AVAIL:
- case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_NOT_REQUIRED:
- wa_level = KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_NOT_REQUIRED;
- break;
- default:
- return -EINVAL;
- }
-
- /*
- * We can deal with NOT_AVAIL on NOT_REQUIRED, but not the
- * other way around.
- */
- if (get_kernel_wa_level(reg->id) < wa_level)
- return -EINVAL;
-
- return 0;
- default:
- return -ENOENT;
- }
-
- return -EINVAL;
-}
diff --git a/include/kvm/arm_hypercalls.h b/include/kvm/arm_hypercalls.h
index 0e2509d27910..5d38628a8d04 100644
--- a/include/kvm/arm_hypercalls.h
+++ b/include/kvm/arm_hypercalls.h
@@ -40,4 +40,11 @@ static inline void smccc_set_retval(struct kvm_vcpu *vcpu,
vcpu_set_reg(vcpu, 3, a3);
}

+struct kvm_one_reg;
+
+int kvm_arm_get_fw_num_regs(struct kvm_vcpu *vcpu);
+int kvm_arm_copy_fw_reg_indices(struct kvm_vcpu *vcpu, u64 __user *uindices);
+int kvm_arm_get_fw_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg);
+int kvm_arm_set_fw_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg);
+
#endif
diff --git a/include/kvm/arm_psci.h b/include/kvm/arm_psci.h
index 68b96c3826c3..6e55b9283789 100644
--- a/include/kvm/arm_psci.h
+++ b/include/kvm/arm_psci.h
@@ -39,11 +39,4 @@ static inline int kvm_psci_version(struct kvm_vcpu *vcpu)

int kvm_psci_call(struct kvm_vcpu *vcpu);

-struct kvm_one_reg;
-
-int kvm_arm_get_fw_num_regs(struct kvm_vcpu *vcpu);
-int kvm_arm_copy_fw_reg_indices(struct kvm_vcpu *vcpu, u64 __user *uindices);
-int kvm_arm_get_fw_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg);
-int kvm_arm_set_fw_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg);
-
#endif /* __KVM_ARM_PSCI_H__ */
--
2.36.0.464.gb9c8b46e94-goog