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arm64: KVM: Hide PMU from guests when disabled

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Since commit 93390c0a1b20 ("arm64: KVM: Hide unsupported AArch64 CPU
features from guests") we can hide cpu features from guests. Apply
this to a long standing issue where guests see a PMU available, but
it's not, because it was not enabled by KVM's userspace.

Signed-off-by: Andrew Jones <drjones@redhat.com>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
This commit is contained in:
Andrew Jones 2017-11-25 18:40:31 +01:00 committed by Christoffer Dall
parent 50c4c4e268
commit 0c0543a128
1 changed files with 21 additions and 14 deletions
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35
arch/arm64/kvm/sys_regs.c
View File

@ -881,18 +881,25 @@ static bool access_cntp_cval(struct kvm_vcpu *vcpu,
} }
/* Read a sanitised cpufeature ID register by sys_reg_desc */ /* Read a sanitised cpufeature ID register by sys_reg_desc */
static u64 read_id_reg(struct sys_reg_desc const *r, bool raz) static u64 read_id_reg(struct kvm_vcpu *vcpu,
struct sys_reg_desc const *r,
bool raz)
{ {
u32 id = sys_reg((u32)r->Op0, (u32)r->Op1, u32 id = sys_reg((u32)r->Op0, (u32)r->Op1,
(u32)r->CRn, (u32)r->CRm, (u32)r->Op2); (u32)r->CRn, (u32)r->CRm, (u32)r->Op2);
u64 val = raz ? 0 : read_sanitised_ftr_reg(id); u64 val = raz ? 0 : read_sanitised_ftr_reg(id);
if (id == SYS_ID_AA64PFR0_EL1) { switch (id) {
case SYS_ID_AA64DFR0_EL1:
if (!kvm_arm_pmu_v3_ready(vcpu))
val &= ~(0xfUL << ID_AA64DFR0_PMUVER_SHIFT);
break;
case SYS_ID_AA64PFR0_EL1:
if (val & (0xfUL << ID_AA64PFR0_SVE_SHIFT)) if (val & (0xfUL << ID_AA64PFR0_SVE_SHIFT))
pr_err_once("kvm [%i]: SVE unsupported for guests, suppressing\n", pr_err_once("kvm [%i]: SVE unsupported for guests, suppressing\n",
task_pid_nr(current)); task_pid_nr(current));
val &= ~(0xfUL << ID_AA64PFR0_SVE_SHIFT); val &= ~(0xfUL << ID_AA64PFR0_SVE_SHIFT);
break;
} }
return val; return val;
@ -908,7 +915,7 @@ static bool __access_id_reg(struct kvm_vcpu *vcpu,
if (p->is_write) if (p->is_write)
return write_to_read_only(vcpu, p, r); return write_to_read_only(vcpu, p, r);
p->regval = read_id_reg(r, raz); p->regval = read_id_reg(vcpu, r, raz);
return true; return true;
} }
@ -937,17 +944,17 @@ static u64 sys_reg_to_index(const struct sys_reg_desc *reg);
* are stored, and for set_id_reg() we don't allow the effective value * are stored, and for set_id_reg() we don't allow the effective value
* to be changed. * to be changed.
*/ */
static int __get_id_reg(const struct sys_reg_desc *rd, void __user *uaddr, static int __get_id_reg(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
bool raz) void __user *uaddr, bool raz)
{ {
const u64 id = sys_reg_to_index(rd); const u64 id = sys_reg_to_index(rd);
const u64 val = read_id_reg(rd, raz); const u64 val = read_id_reg(vcpu, rd, raz);
return reg_to_user(uaddr, &val, id); return reg_to_user(uaddr, &val, id);
} }
static int __set_id_reg(const struct sys_reg_desc *rd, void __user *uaddr, static int __set_id_reg(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
bool raz) void __user *uaddr, bool raz)
{ {
const u64 id = sys_reg_to_index(rd); const u64 id = sys_reg_to_index(rd);
int err; int err;
@ -958,7 +965,7 @@ static int __set_id_reg(const struct sys_reg_desc *rd, void __user *uaddr,
return err; return err;
/* This is what we mean by invariant: you can't change it. */ /* This is what we mean by invariant: you can't change it. */
if (val != read_id_reg(rd, raz)) if (val != read_id_reg(vcpu, rd, raz))
return -EINVAL; return -EINVAL;
return 0; return 0;
@ -967,25 +974,25 @@ static int __set_id_reg(const struct sys_reg_desc *rd, void __user *uaddr,
static int get_id_reg(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd, static int get_id_reg(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
const struct kvm_one_reg *reg, void __user *uaddr) const struct kvm_one_reg *reg, void __user *uaddr)
{ {
return __get_id_reg(rd, uaddr, false); return __get_id_reg(vcpu, rd, uaddr, false);
} }
static int set_id_reg(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd, static int set_id_reg(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
const struct kvm_one_reg *reg, void __user *uaddr) const struct kvm_one_reg *reg, void __user *uaddr)
{ {
return __set_id_reg(rd, uaddr, false); return __set_id_reg(vcpu, rd, uaddr, false);
} }
static int get_raz_id_reg(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd, static int get_raz_id_reg(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
const struct kvm_one_reg *reg, void __user *uaddr) const struct kvm_one_reg *reg, void __user *uaddr)
{ {
return __get_id_reg(rd, uaddr, true); return __get_id_reg(vcpu, rd, uaddr, true);
} }
static int set_raz_id_reg(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd, static int set_raz_id_reg(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
const struct kvm_one_reg *reg, void __user *uaddr) const struct kvm_one_reg *reg, void __user *uaddr)
{ {
return __set_id_reg(rd, uaddr, true); return __set_id_reg(vcpu, rd, uaddr, true);
} }
/* sys_reg_desc initialiser for known cpufeature ID registers */ /* sys_reg_desc initialiser for known cpufeature ID registers */