[PATCH v5 5/6] KVM: arm64: Introduce ID register specific descriptor
Jing Zhang
jingzhangos at google.com
Sun Apr 2 11:37:34 PDT 2023
Introduce an ID feature register specific descriptor to include ID
register specific fields and callbacks besides its corresponding
general system register descriptor.
No functional change intended.
Co-developed-by: Reiji Watanabe <reijiw at google.com>
Signed-off-by: Reiji Watanabe <reijiw at google.com>
Signed-off-by: Jing Zhang <jingzhangos at google.com>
---
arch/arm64/kvm/id_regs.c | 233 ++++++++++++++++++++++++++++----------
arch/arm64/kvm/sys_regs.c | 2 +-
arch/arm64/kvm/sys_regs.h | 1 +
3 files changed, 178 insertions(+), 58 deletions(-)
diff --git a/arch/arm64/kvm/id_regs.c b/arch/arm64/kvm/id_regs.c
index e92eacb0ad32..af86001e2686 100644
--- a/arch/arm64/kvm/id_regs.c
+++ b/arch/arm64/kvm/id_regs.c
@@ -18,6 +18,27 @@
#include "sys_regs.h"
+struct id_reg_desc {
+ const struct sys_reg_desc reg_desc;
+ /*
+ * ftr_bits points to the feature bits array defined in cpufeature.c for
+ * writable CPU ID feature register.
+ */
+ const struct arm64_ftr_bits *ftr_bits;
+ /*
+ * Only bits with 1 are writable from userspace.
+ * This mask might not be necessary in the future whenever all ID
+ * registers are enabled as writable from userspace.
+ */
+ const u64 writable_mask;
+ /*
+ * This function returns the KVM sanitised register value.
+ * The value would be the same as the host kernel sanitised value if
+ * there is no KVM sanitisation for this id register.
+ */
+ u64 (*read_kvm_sanitised_reg)(const struct id_reg_desc *idr);
+};
+
static u8 vcpu_pmuver(const struct kvm_vcpu *vcpu)
{
if (kvm_vcpu_has_pmu(vcpu))
@@ -193,6 +214,11 @@ static unsigned int aa32_id_visibility(const struct kvm_vcpu *vcpu,
return id_visibility(vcpu, r);
}
+static u64 general_read_kvm_sanitised_reg(const struct id_reg_desc *idr)
+{
+ return read_sanitised_ftr_reg(reg_to_encoding(&idr->reg_desc));
+}
+
static int set_id_aa64pfr0_el1(struct kvm_vcpu *vcpu,
const struct sys_reg_desc *rd,
u64 val)
@@ -328,21 +354,31 @@ static int set_id_dfr0_el1(struct kvm_vcpu *vcpu,
}
/* sys_reg_desc initialiser for known cpufeature ID registers */
-#define ID_SANITISED(name) { \
- SYS_DESC(SYS_##name), \
- .access = access_id_reg, \
- .get_user = get_id_reg, \
- .set_user = set_id_reg, \
- .visibility = id_visibility, \
+#define ID_SANITISED(name) { \
+ .reg_desc = { \
+ SYS_DESC(SYS_##name), \
+ .access = access_id_reg, \
+ .get_user = get_id_reg, \
+ .set_user = set_id_reg, \
+ .visibility = id_visibility, \
+ }, \
+ .ftr_bits = NULL, \
+ .writable_mask = 0, \
+ .read_kvm_sanitised_reg = general_read_kvm_sanitised_reg, \
}
/* sys_reg_desc initialiser for known cpufeature ID registers */
-#define AA32_ID_SANITISED(name) { \
- SYS_DESC(SYS_##name), \
- .access = access_id_reg, \
- .get_user = get_id_reg, \
- .set_user = set_id_reg, \
- .visibility = aa32_id_visibility, \
+#define AA32_ID_SANITISED(name) { \
+ .reg_desc = { \
+ SYS_DESC(SYS_##name), \
+ .access = access_id_reg, \
+ .get_user = get_id_reg, \
+ .set_user = set_id_reg, \
+ .visibility = aa32_id_visibility, \
+ }, \
+ .ftr_bits = NULL, \
+ .writable_mask = 0, \
+ .read_kvm_sanitised_reg = general_read_kvm_sanitised_reg, \
}
/*
@@ -350,12 +386,17 @@ static int set_id_dfr0_el1(struct kvm_vcpu *vcpu,
* register with encoding Op0=3, Op1=0, CRn=0, CRm=crm, Op2=op2
* (1 <= crm < 8, 0 <= Op2 < 8).
*/
-#define ID_UNALLOCATED(crm, op2) { \
- Op0(3), Op1(0), CRn(0), CRm(crm), Op2(op2), \
- .access = access_id_reg, \
- .get_user = get_id_reg, \
- .set_user = set_id_reg, \
- .visibility = raz_visibility \
+#define ID_UNALLOCATED(crm, op2) { \
+ .reg_desc = { \
+ Op0(3), Op1(0), CRn(0), CRm(crm), Op2(op2), \
+ .access = access_id_reg, \
+ .get_user = get_id_reg, \
+ .set_user = set_id_reg, \
+ .visibility = raz_visibility \
+ }, \
+ .ftr_bits = NULL, \
+ .writable_mask = 0, \
+ .read_kvm_sanitised_reg = NULL, \
}
/*
@@ -363,15 +404,20 @@ static int set_id_dfr0_el1(struct kvm_vcpu *vcpu,
* For now, these are exposed just like unallocated ID regs: they appear
* RAZ for the guest.
*/
-#define ID_HIDDEN(name) { \
- SYS_DESC(SYS_##name), \
- .access = access_id_reg, \
- .get_user = get_id_reg, \
- .set_user = set_id_reg, \
- .visibility = raz_visibility, \
+#define ID_HIDDEN(name) { \
+ .reg_desc = { \
+ SYS_DESC(SYS_##name), \
+ .access = access_id_reg, \
+ .get_user = get_id_reg, \
+ .set_user = set_id_reg, \
+ .visibility = raz_visibility, \
+ }, \
+ .ftr_bits = NULL, \
+ .writable_mask = 0, \
+ .read_kvm_sanitised_reg = NULL, \
}
-static const struct sys_reg_desc id_reg_descs[] = {
+static const struct id_reg_desc id_reg_descs[KVM_ARM_ID_REG_NUM] = {
/*
* ID regs: all ID_SANITISED() entries here must have corresponding
* entries in arm64_ftr_regs[].
@@ -381,9 +427,13 @@ static const struct sys_reg_desc id_reg_descs[] = {
/* CRm=1 */
AA32_ID_SANITISED(ID_PFR0_EL1),
AA32_ID_SANITISED(ID_PFR1_EL1),
- { SYS_DESC(SYS_ID_DFR0_EL1), .access = access_id_reg,
- .get_user = get_id_reg, .set_user = set_id_dfr0_el1,
- .visibility = aa32_id_visibility, },
+ { .reg_desc = {
+ SYS_DESC(SYS_ID_DFR0_EL1),
+ .access = access_id_reg,
+ .get_user = get_id_reg,
+ .set_user = set_id_dfr0_el1,
+ .visibility = aa32_id_visibility, },
+ },
ID_HIDDEN(ID_AFR0_EL1),
AA32_ID_SANITISED(ID_MMFR0_EL1),
AA32_ID_SANITISED(ID_MMFR1_EL1),
@@ -412,8 +462,12 @@ static const struct sys_reg_desc id_reg_descs[] = {
/* AArch64 ID registers */
/* CRm=4 */
- { SYS_DESC(SYS_ID_AA64PFR0_EL1), .access = access_id_reg,
- .get_user = get_id_reg, .set_user = set_id_aa64pfr0_el1, },
+ { .reg_desc = {
+ SYS_DESC(SYS_ID_AA64PFR0_EL1),
+ .access = access_id_reg,
+ .get_user = get_id_reg,
+ .set_user = set_id_aa64pfr0_el1, },
+ },
ID_SANITISED(ID_AA64PFR1_EL1),
ID_UNALLOCATED(4, 2),
ID_UNALLOCATED(4, 3),
@@ -423,8 +477,12 @@ static const struct sys_reg_desc id_reg_descs[] = {
ID_UNALLOCATED(4, 7),
/* CRm=5 */
- { SYS_DESC(SYS_ID_AA64DFR0_EL1), .access = access_id_reg,
- .get_user = get_id_reg, .set_user = set_id_aa64dfr0_el1, },
+ { .reg_desc = {
+ SYS_DESC(SYS_ID_AA64DFR0_EL1),
+ .access = access_id_reg,
+ .get_user = get_id_reg,
+ .set_user = set_id_aa64dfr0_el1, },
+ },
ID_SANITISED(ID_AA64DFR1_EL1),
ID_UNALLOCATED(5, 2),
ID_UNALLOCATED(5, 3),
@@ -454,6 +512,17 @@ static const struct sys_reg_desc id_reg_descs[] = {
ID_UNALLOCATED(7, 7),
};
+static const struct sys_reg_desc *id_params_to_desc(struct sys_reg_params *params)
+{
+ u32 id;
+
+ id = reg_to_encoding(params);
+ if (is_id_reg(id))
+ return &id_reg_descs[IDREG_IDX(id)].reg_desc;
+
+ return NULL;
+}
+
/**
* emulate_id_reg - Emulate a guest access to an AArch64 CPU ID feature register
* @vcpu: The VCPU pointer
@@ -465,9 +534,9 @@ int emulate_id_reg(struct kvm_vcpu *vcpu, struct sys_reg_params *params)
{
const struct sys_reg_desc *r;
- r = find_reg(params, id_reg_descs, ARRAY_SIZE(id_reg_descs));
+ r = id_params_to_desc(params);
- if (likely(r)) {
+ if (r) {
perform_access(vcpu, params, r);
} else {
print_sys_reg_msg(params,
@@ -481,32 +550,91 @@ int emulate_id_reg(struct kvm_vcpu *vcpu, struct sys_reg_params *params)
int kvm_arm_get_id_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
{
- return kvm_sys_reg_get_user(vcpu, reg,
- id_reg_descs, ARRAY_SIZE(id_reg_descs));
+ u64 __user *uaddr = (u64 __user *)(unsigned long)reg->addr;
+ const struct sys_reg_desc *r;
+ struct sys_reg_params params;
+ u64 val;
+ int ret;
+
+ if (!index_to_params(reg->id, ¶ms))
+ return -ENOENT;
+
+ r = id_params_to_desc(¶ms);
+ if (!r)
+ return -ENOENT;
+
+ if (r->get_user) {
+ ret = (r->get_user)(vcpu, r, &val);
+ } else {
+ ret = 0;
+ val = IDREG(vcpu->kvm, reg_to_encoding(r));
+ }
+
+ if (!ret)
+ ret = put_user(val, uaddr);
+
+ return ret;
}
int kvm_arm_set_id_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
{
- return kvm_sys_reg_set_user(vcpu, reg,
- id_reg_descs, ARRAY_SIZE(id_reg_descs));
+ u64 __user *uaddr = (u64 __user *)(unsigned long)reg->addr;
+ const struct sys_reg_desc *r;
+ struct sys_reg_params params;
+ u64 val;
+ int ret;
+
+ if (!index_to_params(reg->id, ¶ms))
+ return -ENOENT;
+
+ r = id_params_to_desc(¶ms);
+ if (!r)
+ return -ENOENT;
+
+ if (get_user(val, uaddr))
+ return -EFAULT;
+
+ if (sysreg_user_write_ignore(vcpu, r))
+ return 0;
+
+ if (r->set_user) {
+ ret = (r->set_user)(vcpu, r, val);
+ } else {
+ WARN_ONCE(1, "ID register set_user callback is NULL\n");
+ ret = 0;
+ }
+
+ return ret;
}
bool kvm_arm_check_idreg_table(void)
{
- return check_sysreg_table(id_reg_descs, ARRAY_SIZE(id_reg_descs), false);
+ unsigned int i;
+
+ for (i = 0; i < ARRAY_SIZE(id_reg_descs); i++) {
+ const struct sys_reg_desc *r = &id_reg_descs[i].reg_desc;
+
+ if (!is_id_reg(reg_to_encoding(r))) {
+ kvm_err("id_reg table %pS entry %d not set correctly\n",
+ &id_reg_descs[i].reg_desc, i);
+ return false;
+ }
+ }
+
+ return true;
}
int kvm_arm_walk_id_regs(struct kvm_vcpu *vcpu, u64 __user *uind)
{
- const struct sys_reg_desc *i2, *end2;
+ const struct id_reg_desc *i2, *end2;
unsigned int total = 0;
int err;
i2 = id_reg_descs;
end2 = id_reg_descs + ARRAY_SIZE(id_reg_descs);
- while (i2 != end2) {
- err = walk_one_sys_reg(vcpu, i2++, &uind, &total);
+ for (; i2 != end2; i2++) {
+ err = walk_one_sys_reg(vcpu, &(i2->reg_desc), &uind, &total);
if (err)
return err;
}
@@ -524,21 +652,12 @@ void kvm_arm_init_id_regs(struct kvm *kvm)
u64 val;
for (i = 0; i < ARRAY_SIZE(id_reg_descs); i++) {
- id = reg_to_encoding(&id_reg_descs[i]);
- if (WARN_ON_ONCE(!is_id_reg(id)))
- /* Shouldn't happen */
- continue;
-
- /*
- * Some hidden ID registers which are not in arm64_ftr_regs[]
- * would cause warnings from read_sanitised_ftr_reg().
- * Skip those ID registers to avoid the warnings.
- */
- if (id_reg_descs[i].visibility == raz_visibility)
- /* Hidden or reserved ID register */
- continue;
-
- val = read_sanitised_ftr_reg(id);
+ id = reg_to_encoding(&id_reg_descs[i].reg_desc);
+
+ val = 0;
+ if (id_reg_descs[i].read_kvm_sanitised_reg)
+ val = id_reg_descs[i].read_kvm_sanitised_reg(&id_reg_descs[i]);
+
IDREG(kvm, id) = val;
}
diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index 3af9f85aa976..1d7fb0acf154 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -2541,7 +2541,7 @@ int kvm_handle_sys_reg(struct kvm_vcpu *vcpu)
* Userspace API
*****************************************************************************/
-static bool index_to_params(u64 id, struct sys_reg_params *params)
+bool index_to_params(u64 id, struct sys_reg_params *params)
{
switch (id & KVM_REG_SIZE_MASK) {
case KVM_REG_SIZE_U64:
diff --git a/arch/arm64/kvm/sys_regs.h b/arch/arm64/kvm/sys_regs.h
index 326ca28c1117..15a0a1e2fe99 100644
--- a/arch/arm64/kvm/sys_regs.h
+++ b/arch/arm64/kvm/sys_regs.h
@@ -223,6 +223,7 @@ static inline bool is_id_reg(u32 id)
void perform_access(struct kvm_vcpu *vcpu, struct sys_reg_params *params,
const struct sys_reg_desc *r);
+bool index_to_params(u64 id, struct sys_reg_params *params);
const struct sys_reg_desc *get_reg_by_id(u64 id,
const struct sys_reg_desc table[],
unsigned int num);
--
2.40.0.348.gf938b09366-goog
More information about the linux-arm-kernel
mailing list