The psuedo-firmware registers, KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_1
and KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2, can be scopped as per-VM
registers. Hence, during the KVM_GET_REG_LIST call, encode
KVM_REG_ARM_SCOPE_VM into the registers, but during
KVM_[GET|SET]_ONE_REG calls, clear the scope information such that
they can be processed like before.
For future expansion, helper functions such as
kvm_arm_reg_id_encode_scope() and kvm_arm_reg_id_clear_scope()
are introduced.
Signed-off-by: Raghavendra Rao Ananta <rananta@xxxxxxxxxx>
---
arch/arm64/include/asm/kvm_host.h | 2 +
arch/arm64/kvm/guest.c | 77 +++++++++++++++++++++++++++++++
arch/arm64/kvm/hypercalls.c | 31 +++++++++----
3 files changed, 100 insertions(+), 10 deletions(-)
diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index 8132de6bd718..657733554d98 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -794,6 +794,8 @@ bool kvm_arm_vcpu_is_finalized(struct kvm_vcpu *vcpu);
(test_bit(KVM_ARM_VCPU_PMU_V3, (vcpu)->arch.features))
int kvm_trng_call(struct kvm_vcpu *vcpu);
+int kvm_arm_reg_id_encode_scope(struct kvm_vcpu *vcpu, u64 *reg_id);
+void kvm_arm_reg_id_clear_scope(struct kvm_vcpu *vcpu, u64 *reg_id);
#ifdef CONFIG_KVM
extern phys_addr_t hyp_mem_base;
extern phys_addr_t hyp_mem_size;
diff --git a/arch/arm64/kvm/guest.c b/arch/arm64/kvm/guest.c
index 8238e52d890d..eb061e64a7a5 100644
--- a/arch/arm64/kvm/guest.c
+++ b/arch/arm64/kvm/guest.c
@@ -61,6 +61,83 @@ const struct kvm_stats_header kvm_vcpu_stats_header = {
sizeof(kvm_vcpu_stats_desc),
};
+/* Registers that are VM scopped */
+static const u64 kvm_arm_vm_scope_fw_regs[] = {
+ KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_1,
+ KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2,
+};
+
+/**
+ * kvm_arm_reg_id_encode_scope - Encode the KVM_REG_ARM_SCOPE info into the
+ * register-id
+ * @vcpu: The vcpu pointer
+ * @reg_id: Pointer to the register
+ *
+ * The function adds the register's scoping information into its encoding.
+ * If it's explicitly marked as a per-VM register, it's encoded with
+ * KVM_REG_ARM_SCOPE_VM. Else, it's marked as KVM_REG_ARM_SCOPE_VCPU, which
+ * is also the default if KVM_CAP_ARM_REG_SCOPE is disabled.
+ *
+ * For any error cases, the function returns an error code, else it returns
+ * the integer value of the encoding.
+ */
+int kvm_arm_reg_id_encode_scope(struct kvm_vcpu *vcpu, u64 *reg_id)
+{
+ const u64 *vm_scope_reg_arr;
+ unsigned int arr_size, idx;
+
+ if (!READ_ONCE(vcpu->kvm->arch.reg_scope_enabled))
+ return KVM_REG_ARM_SCOPE_VCPU;
+
+ if (!reg_id)
+ return -EINVAL;
+
+ switch (*reg_id & KVM_REG_ARM_COPROC_MASK) {
+ case KVM_REG_ARM_FW:
+ vm_scope_reg_arr = kvm_arm_vm_scope_fw_regs;
+ arr_size = ARRAY_SIZE(kvm_arm_vm_scope_fw_regs);
+ break;
+ default:
+ /* All the other register classes are currently
+ * treated as per-vCPU registers.
+ */
+ return KVM_REG_ARM_SCOPE_VCPU;
+ }
+
+ /* By default, all the registers encodings are scoped as vCPU.
+ * Modify the scope only if a register is marked as per-VM.
+ */
+ for (idx = 0; idx < arr_size; idx++) {
+ if (vm_scope_reg_arr[idx] == *reg_id) {
+ *reg_id |=
+ KVM_REG_ARM_SCOPE_VM << KVM_REG_ARM_SCOPE_SHIFT;
+ return KVM_REG_ARM_SCOPE_VM;
+ }
+ }
+
+ return KVM_REG_ARM_SCOPE_VCPU;
+}
+
+/**
+ * kvm_arm_reg_id_clear_scope - Clear the KVM_REG_ARM_SCOPE info from the
+ * register-id
+ * @vcpu: The vcpu pointer
+ * @reg_id: Pointer to the register
+ *
+ * The function clears the register's scoping information, which ultimately
+ * is the raw encoding of the register. Note that the result is same as that
+ * of re-encoding the register as KVM_REG_ARM_SCOPE_VCPU.
+ * The function can be helpful to the existing code that uses the original
+ * register encoding to operate on the register.
+ */
+void kvm_arm_reg_id_clear_scope(struct kvm_vcpu *vcpu, u64 *reg_id)
+{
+ if (!READ_ONCE(vcpu->kvm->arch.reg_scope_enabled) || !reg_id)
+ return;
+
+ *reg_id &= ~(1 << KVM_REG_ARM_SCOPE_SHIFT);
+}
+
static bool core_reg_offset_is_vreg(u64 off)
{
return off >= KVM_REG_ARM_CORE_REG(fp_regs.vregs) &&
diff --git a/arch/arm64/kvm/hypercalls.c b/arch/arm64/kvm/hypercalls.c
index 3c2fcf31ad3d..8624e6964940 100644
--- a/arch/arm64/kvm/hypercalls.c
+++ b/arch/arm64/kvm/hypercalls.c
@@ -160,10 +160,17 @@ 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 i;
+ int i, ret;
+ u64 reg_id;
for (i = 0; i < ARRAY_SIZE(kvm_arm_fw_reg_ids); i++) {
- if (put_user(kvm_arm_fw_reg_ids[i], uindices++))
+ reg_id = kvm_arm_fw_reg_ids[i];
+
+ ret = kvm_arm_reg_id_encode_scope(vcpu, ®_id);
+ if (ret < 0)
+ return ret;
+
+ if (put_user(reg_id, uindices++))
return -EFAULT;
}
@@ -214,21 +221,23 @@ static int get_kernel_wa_level(u64 regid)
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;
+ u64 val, reg_id = reg->id;
- switch (reg->id) {
+ kvm_arm_reg_id_clear_scope(vcpu, ®_id);
+
+ switch (reg_id) {
case KVM_REG_ARM_PSCI_VERSION:
val = kvm_psci_version(vcpu, vcpu->kvm);
break;
case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_1:
case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2:
- val = get_kernel_wa_level(reg->id) & KVM_REG_FEATURE_LEVEL_MASK;
+ 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)))
+ if (copy_to_user(uaddr, &val, KVM_REG_SIZE(reg_id)))
return -EFAULT;
return 0;
@@ -237,13 +246,15 @@ 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)
{
void __user *uaddr = (void __user *)(long)reg->addr;
- u64 val;
+ u64 val, reg_id = reg->id;
int wa_level;
if (copy_from_user(&val, uaddr, KVM_REG_SIZE(reg->id)))
return -EFAULT;
- switch (reg->id) {
+ kvm_arm_reg_id_clear_scope(vcpu, ®_id);
+
+ switch (reg_id) {
case KVM_REG_ARM_PSCI_VERSION:
{
bool wants_02;
@@ -270,7 +281,7 @@ int kvm_arm_set_fw_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
if (val & ~KVM_REG_FEATURE_LEVEL_MASK)
return -EINVAL;
- if (get_kernel_wa_level(reg->id) < val)
+ if (get_kernel_wa_level(reg_id) < val)
return -EINVAL;
return 0;
@@ -306,7 +317,7 @@ int kvm_arm_set_fw_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
* We can deal with NOT_AVAIL on NOT_REQUIRED, but not the
* other way around.
*/
- if (get_kernel_wa_level(reg->id) < wa_level)
+ if (get_kernel_wa_level(reg_id) < wa_level)
return -EINVAL;
return 0;
--
2.35.1.473.g83b2b277ed-goog
