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Message-ID: <20250210154953.27002-4-sebott@redhat.com>
Date: Mon, 10 Feb 2025 16:49:52 +0100
From: Sebastian Ott <sebott@...hat.com>
To: Marc Zyngier <maz@...nel.org>,
Oliver Upton <oliver.upton@...ux.dev>,
Joey Gouly <joey.gouly@....com>,
Suzuki K Poulose <suzuki.poulose@....com>,
Zenghui Yu <yuzenghui@...wei.com>,
Catalin Marinas <catalin.marinas@....com>,
Will Deacon <will@...nel.org>,
Shameer Kolothum <shameerali.kolothum.thodi@...wei.com>
Cc: Cornelia Huck <cohuck@...hat.com>,
Eric Auger <eric.auger@...hat.com>,
linux-arm-kernel@...ts.infradead.org,
kvmarm@...ts.linux.dev,
linux-kernel@...r.kernel.org
Subject: [PATCH 3/4] KVM: arm64: Allow userspace to change AIDR_EL1
Enable VMMs to write AIDR_EL1 by treating it as a VM ID register.
Since this was the last invariant register remove all the stuff
that was needed to handle these.
Signed-off-by: Sebastian Ott <sebott@...hat.com>
---
arch/arm64/include/asm/kvm_host.h | 3 ++
arch/arm64/kvm/sys_regs.c | 90 +++----------------------------
2 files changed, 10 insertions(+), 83 deletions(-)
diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index c8fba4111b77..de735e2ad9ce 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -375,6 +375,7 @@ struct kvm_arch {
u64 midr_el1;
u64 revidr_el1;
+ u64 aidr_el1;
u64 ctr_el0;
/* Masks for VNCR-backed and general EL2 sysregs */
@@ -1475,6 +1476,8 @@ static inline u64 *__vm_id_reg(struct kvm_arch *ka, u32 reg)
return &ka->midr_el1;
case SYS_REVIDR_EL1:
return &ka->revidr_el1;
+ case SYS_AIDR_EL1:
+ return &ka->aidr_el1;
case SYS_CTR_EL0:
return &ka->ctr_el0;
default:
diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index 0ab2b2c79881..7d588fedb50a 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -1667,7 +1667,7 @@ static bool is_feature_id_reg(u32 encoding)
static inline bool is_vm_ftr_id_reg(u32 id)
{
if (id == SYS_CTR_EL0 || id == SYS_MIDR_EL1 ||
- id == SYS_REVIDR_EL1)
+ id == SYS_REVIDR_EL1 || id == SYS_AIDR_EL1)
return true;
return (sys_reg_Op0(id) == 3 && sys_reg_Op1(id) == 0 &&
@@ -2003,7 +2003,8 @@ static int get_id_reg(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
static bool skip_feature_check(u32 reg)
{
return (reg == SYS_MIDR_EL1) ||
- (reg == SYS_REVIDR_EL1);
+ (reg == SYS_REVIDR_EL1) ||
+ (reg == SYS_AIDR_EL1);
}
/*
@@ -2524,6 +2525,7 @@ static bool access_mdcr(struct kvm_vcpu *vcpu,
FUNCTION_RESET(midr_el1)
FUNCTION_RESET(revidr_el1)
+FUNCTION_RESET(aidr_el1)
/*
@@ -2850,6 +2852,8 @@ static const struct sys_reg_desc sys_reg_descs[] = {
.set_user = set_clidr, .val = ~CLIDR_EL1_RES0 },
{ SYS_DESC(SYS_CCSIDR2_EL1), undef_access },
{ SYS_DESC(SYS_SMIDR_EL1), undef_access },
+ { ID_DESC(AIDR_EL1), .set_user = set_id_reg, .visibility = id_visibility,
+ .reset = reset_aidr_el1, .val = -1ULL },
{ SYS_DESC(SYS_CSSELR_EL1), access_csselr, reset_unknown, CSSELR_EL1 },
ID_FILTERED(CTR_EL0, ctr_el0,
CTR_EL0_DIC_MASK |
@@ -4614,61 +4618,6 @@ id_to_sys_reg_desc(struct kvm_vcpu *vcpu, u64 id,
return r;
}
-/*
- * These are the invariant sys_reg registers: we let the guest see the
- * host versions of these, so they're part of the guest state.
- *
- * A future CPU may provide a mechanism to present different values to
- * the guest, or a future kvm may trap them.
- */
-
-#define FUNCTION_INVARIANT(reg) \
- static u64 reset_##reg(struct kvm_vcpu *v, \
- const struct sys_reg_desc *r) \
- { \
- ((struct sys_reg_desc *)r)->val = read_sysreg(reg); \
- return ((struct sys_reg_desc *)r)->val; \
- }
-
-FUNCTION_INVARIANT(aidr_el1)
-
-/* ->val is filled in by kvm_sys_reg_table_init() */
-static struct sys_reg_desc invariant_sys_regs[] __ro_after_init = {
- { SYS_DESC(SYS_AIDR_EL1), NULL, reset_aidr_el1 },
-};
-
-static int get_invariant_sys_reg(u64 id, u64 __user *uaddr)
-{
- const struct sys_reg_desc *r;
-
- r = get_reg_by_id(id, invariant_sys_regs,
- ARRAY_SIZE(invariant_sys_regs));
- if (!r)
- return -ENOENT;
-
- return put_user(r->val, uaddr);
-}
-
-static int set_invariant_sys_reg(u64 id, u64 __user *uaddr)
-{
- const struct sys_reg_desc *r;
- u64 val;
-
- r = get_reg_by_id(id, invariant_sys_regs,
- ARRAY_SIZE(invariant_sys_regs));
- if (!r)
- return -ENOENT;
-
- if (get_user(val, uaddr))
- return -EFAULT;
-
- /* This is what we mean by invariant: you can't change it. */
- if (r->val != val)
- return -EINVAL;
-
- return 0;
-}
-
static int demux_c15_get(struct kvm_vcpu *vcpu, u64 id, void __user *uaddr)
{
u32 val;
@@ -4750,15 +4699,10 @@ int kvm_sys_reg_get_user(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg,
int kvm_arm_sys_reg_get_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
{
void __user *uaddr = (void __user *)(unsigned long)reg->addr;
- int err;
if ((reg->id & KVM_REG_ARM_COPROC_MASK) == KVM_REG_ARM_DEMUX)
return demux_c15_get(vcpu, reg->id, uaddr);
- err = get_invariant_sys_reg(reg->id, uaddr);
- if (err != -ENOENT)
- return err;
-
return kvm_sys_reg_get_user(vcpu, reg,
sys_reg_descs, ARRAY_SIZE(sys_reg_descs));
}
@@ -4794,15 +4738,10 @@ int kvm_sys_reg_set_user(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg,
int kvm_arm_sys_reg_set_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
{
void __user *uaddr = (void __user *)(unsigned long)reg->addr;
- int err;
if ((reg->id & KVM_REG_ARM_COPROC_MASK) == KVM_REG_ARM_DEMUX)
return demux_c15_set(vcpu, reg->id, uaddr);
- err = set_invariant_sys_reg(reg->id, uaddr);
- if (err != -ENOENT)
- return err;
-
return kvm_sys_reg_set_user(vcpu, reg,
sys_reg_descs, ARRAY_SIZE(sys_reg_descs));
}
@@ -4891,23 +4830,13 @@ static int walk_sys_regs(struct kvm_vcpu *vcpu, u64 __user *uind)
unsigned long kvm_arm_num_sys_reg_descs(struct kvm_vcpu *vcpu)
{
- return ARRAY_SIZE(invariant_sys_regs)
- + num_demux_regs()
- + walk_sys_regs(vcpu, (u64 __user *)NULL);
+ return num_demux_regs() + walk_sys_regs(vcpu, (u64 __user *)NULL);
}
int kvm_arm_copy_sys_reg_indices(struct kvm_vcpu *vcpu, u64 __user *uindices)
{
- unsigned int i;
int err;
- /* Then give them all the invariant registers' indices. */
- for (i = 0; i < ARRAY_SIZE(invariant_sys_regs); i++) {
- if (put_user(sys_reg_to_index(&invariant_sys_regs[i]), uindices))
- return -EFAULT;
- uindices++;
- }
-
err = walk_sys_regs(vcpu, uindices);
if (err < 0)
return err;
@@ -5133,16 +5062,11 @@ int __init kvm_sys_reg_table_init(void)
valid &= check_sysreg_table(cp14_64_regs, ARRAY_SIZE(cp14_64_regs), true);
valid &= check_sysreg_table(cp15_regs, ARRAY_SIZE(cp15_regs), true);
valid &= check_sysreg_table(cp15_64_regs, ARRAY_SIZE(cp15_64_regs), true);
- valid &= check_sysreg_table(invariant_sys_regs, ARRAY_SIZE(invariant_sys_regs), false);
valid &= check_sysreg_table(sys_insn_descs, ARRAY_SIZE(sys_insn_descs), false);
if (!valid)
return -EINVAL;
- /* We abuse the reset function to overwrite the table itself. */
- for (i = 0; i < ARRAY_SIZE(invariant_sys_regs); i++)
- invariant_sys_regs[i].reset(NULL, &invariant_sys_regs[i]);
-
ret = populate_nv_trap_config();
for (i = 0; !ret && i < ARRAY_SIZE(sys_reg_descs); i++)
--
2.42.0
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