From 3f9cd0ca848413fd368278310d2cdd6c2bef48b2 Mon Sep 17 00:00:00 2001 From: Jing Zhang Date: Tue, 3 Oct 2023 23:03:57 +0000 Subject: KVM: arm64: Allow userspace to get the writable masks for feature ID registers While the Feature ID range is well defined and pretty large, it isn't inconceivable that the architecture will eventually grow some other ranges that will need to similarly be described to userspace. Add a VM ioctl to allow userspace to get writable masks for feature ID registers in below system register space: op0 = 3, op1 = {0, 1, 3}, CRn = 0, CRm = {0 - 7}, op2 = {0 - 7} This is used to support mix-and-match userspace and kernels for writable ID registers, where userspace may want to know upfront whether it can actually tweak the contents of an idreg or not. Add a new capability (KVM_CAP_ARM_SUPPORTED_FEATURE_ID_RANGES) that returns a bitmap of the valid ranges, which can subsequently be retrieved, one at a time by setting the index of the set bit as the range identifier. Suggested-by: Marc Zyngier Suggested-by: Cornelia Huck Signed-off-by: Jing Zhang Reviewed-by: Cornelia Huck Reviewed-by: Marc Zyngier Link: https://lore.kernel.org/r/20231003230408.3405722-2-oliver.upton@linux.dev Signed-off-by: Oliver Upton --- arch/arm64/include/asm/kvm_host.h | 2 ++ arch/arm64/include/uapi/asm/kvm.h | 32 +++++++++++++++++++ arch/arm64/kvm/arm.c | 10 ++++++ arch/arm64/kvm/sys_regs.c | 66 +++++++++++++++++++++++++++++++++++++++ 4 files changed, 110 insertions(+) (limited to 'arch/arm64') diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h index af06ccb7ee34..5e3f778f81db 100644 --- a/arch/arm64/include/asm/kvm_host.h +++ b/arch/arm64/include/asm/kvm_host.h @@ -1078,6 +1078,8 @@ int kvm_vm_ioctl_mte_copy_tags(struct kvm *kvm, struct kvm_arm_copy_mte_tags *copy_tags); int kvm_vm_ioctl_set_counter_offset(struct kvm *kvm, struct kvm_arm_counter_offset *offset); +int kvm_vm_ioctl_get_reg_writable_masks(struct kvm *kvm, + struct reg_mask_range *range); /* Guest/host FPSIMD coordination helpers */ int kvm_arch_vcpu_run_map_fp(struct kvm_vcpu *vcpu); diff --git a/arch/arm64/include/uapi/asm/kvm.h b/arch/arm64/include/uapi/asm/kvm.h index f7ddd73a8c0f..89d2fc872d9f 100644 --- a/arch/arm64/include/uapi/asm/kvm.h +++ b/arch/arm64/include/uapi/asm/kvm.h @@ -505,6 +505,38 @@ struct kvm_smccc_filter { #define KVM_HYPERCALL_EXIT_SMC (1U << 0) #define KVM_HYPERCALL_EXIT_16BIT (1U << 1) +/* + * Get feature ID registers userspace writable mask. + * + * From DDI0487J.a, D19.2.66 ("ID_AA64MMFR2_EL1, AArch64 Memory Model + * Feature Register 2"): + * + * "The Feature ID space is defined as the System register space in + * AArch64 with op0==3, op1=={0, 1, 3}, CRn==0, CRm=={0-7}, + * op2=={0-7}." + * + * This covers all currently known R/O registers that indicate + * anything useful feature wise, including the ID registers. + * + * If we ever need to introduce a new range, it will be described as + * such in the range field. + */ +#define KVM_ARM_FEATURE_ID_RANGE_IDX(op0, op1, crn, crm, op2) \ + ({ \ + __u64 __op1 = (op1) & 3; \ + __op1 -= (__op1 == 3); \ + (__op1 << 6 | ((crm) & 7) << 3 | (op2)); \ + }) + +#define KVM_ARM_FEATURE_ID_RANGE 0 +#define KVM_ARM_FEATURE_ID_RANGE_SIZE (3 * 8 * 8) + +struct reg_mask_range { + __u64 addr; /* Pointer to mask array */ + __u32 range; /* Requested range */ + __u32 reserved[13]; +}; + #endif #endif /* __ARM_KVM_H__ */ diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c index 4866b3f7b4ea..f48430ed5b8b 100644 --- a/arch/arm64/kvm/arm.c +++ b/arch/arm64/kvm/arm.c @@ -317,6 +317,9 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext) case KVM_CAP_ARM_SUPPORTED_BLOCK_SIZES: r = kvm_supported_block_sizes(); break; + case KVM_CAP_ARM_SUPPORTED_REG_MASK_RANGES: + r = BIT(0); + break; default: r = 0; } @@ -1629,6 +1632,13 @@ int kvm_arch_vm_ioctl(struct file *filp, unsigned int ioctl, unsigned long arg) return kvm_vm_set_attr(kvm, &attr); } + case KVM_ARM_GET_REG_WRITABLE_MASKS: { + struct reg_mask_range range; + + if (copy_from_user(&range, argp, sizeof(range))) + return -EFAULT; + return kvm_vm_ioctl_get_reg_writable_masks(kvm, &range); + } default: return -EINVAL; } diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c index e92ec810d449..5b0e94367f74 100644 --- a/arch/arm64/kvm/sys_regs.c +++ b/arch/arm64/kvm/sys_regs.c @@ -1373,6 +1373,13 @@ static inline bool is_id_reg(u32 id) sys_reg_CRm(id) < 8); } +static inline bool is_aa32_id_reg(u32 id) +{ + return (sys_reg_Op0(id) == 3 && sys_reg_Op1(id) == 0 && + sys_reg_CRn(id) == 0 && sys_reg_CRm(id) >= 1 && + sys_reg_CRm(id) <= 3); +} + static unsigned int id_visibility(const struct kvm_vcpu *vcpu, const struct sys_reg_desc *r) { @@ -3572,6 +3579,65 @@ int kvm_arm_copy_sys_reg_indices(struct kvm_vcpu *vcpu, u64 __user *uindices) return write_demux_regids(uindices); } +#define KVM_ARM_FEATURE_ID_RANGE_INDEX(r) \ + KVM_ARM_FEATURE_ID_RANGE_IDX(sys_reg_Op0(r), \ + sys_reg_Op1(r), \ + sys_reg_CRn(r), \ + sys_reg_CRm(r), \ + sys_reg_Op2(r)) + +static bool is_feature_id_reg(u32 encoding) +{ + return (sys_reg_Op0(encoding) == 3 && + (sys_reg_Op1(encoding) < 2 || sys_reg_Op1(encoding) == 3) && + sys_reg_CRn(encoding) == 0 && + sys_reg_CRm(encoding) <= 7); +} + +int kvm_vm_ioctl_get_reg_writable_masks(struct kvm *kvm, struct reg_mask_range *range) +{ + const void *zero_page = page_to_virt(ZERO_PAGE(0)); + u64 __user *masks = (u64 __user *)range->addr; + + /* Only feature id range is supported, reserved[13] must be zero. */ + if (range->range || + memcmp(range->reserved, zero_page, sizeof(range->reserved))) + return -EINVAL; + + /* Wipe the whole thing first */ + if (clear_user(masks, KVM_ARM_FEATURE_ID_RANGE_SIZE * sizeof(__u64))) + return -EFAULT; + + for (int i = 0; i < ARRAY_SIZE(sys_reg_descs); i++) { + const struct sys_reg_desc *reg = &sys_reg_descs[i]; + u32 encoding = reg_to_encoding(reg); + u64 val; + + if (!is_feature_id_reg(encoding) || !reg->set_user) + continue; + + /* + * For ID registers, we return the writable mask. Other feature + * registers return a full 64bit mask. That's not necessary + * compliant with a given revision of the architecture, but the + * RES0/RES1 definitions allow us to do that. + */ + if (is_id_reg(encoding)) { + if (!reg->val || + (is_aa32_id_reg(encoding) && !kvm_supports_32bit_el0())) + continue; + val = reg->val; + } else { + val = ~0UL; + } + + if (put_user(val, (masks + KVM_ARM_FEATURE_ID_RANGE_INDEX(encoding)))) + return -EFAULT; + } + + return 0; +} + int __init kvm_sys_reg_table_init(void) { struct sys_reg_params params; -- cgit v1.2.3 From 8b6958d6ace19d56b44ca0f961f4fa480d4b48fc Mon Sep 17 00:00:00 2001 From: Jing Zhang Date: Tue, 3 Oct 2023 23:03:59 +0000 Subject: KVM: arm64: Use guest ID register values for the sake of emulation Since KVM now supports per-VM ID registers, use per-VM ID register values for the sake of emulation for DBGDIDR and LORegion. Signed-off-by: Jing Zhang Reviewed-by: Marc Zyngier Link: https://lore.kernel.org/r/20231003230408.3405722-4-oliver.upton@linux.dev Signed-off-by: Oliver Upton --- arch/arm64/kvm/sys_regs.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'arch/arm64') diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c index 5b0e94367f74..b73f9ff0899b 100644 --- a/arch/arm64/kvm/sys_regs.c +++ b/arch/arm64/kvm/sys_regs.c @@ -379,7 +379,7 @@ static bool trap_loregion(struct kvm_vcpu *vcpu, struct sys_reg_params *p, const struct sys_reg_desc *r) { - u64 val = read_sanitised_ftr_reg(SYS_ID_AA64MMFR1_EL1); + u64 val = IDREG(vcpu->kvm, SYS_ID_AA64MMFR1_EL1); u32 sr = reg_to_encoding(r); if (!(val & (0xfUL << ID_AA64MMFR1_EL1_LO_SHIFT))) { @@ -2445,8 +2445,8 @@ static bool trap_dbgdidr(struct kvm_vcpu *vcpu, if (p->is_write) { return ignore_write(vcpu, p); } else { - u64 dfr = read_sanitised_ftr_reg(SYS_ID_AA64DFR0_EL1); - u64 pfr = read_sanitised_ftr_reg(SYS_ID_AA64PFR0_EL1); + u64 dfr = IDREG(vcpu->kvm, SYS_ID_AA64DFR0_EL1); + u64 pfr = IDREG(vcpu->kvm, SYS_ID_AA64PFR0_EL1); u32 el3 = !!cpuid_feature_extract_unsigned_field(pfr, ID_AA64PFR0_EL1_EL3_SHIFT); p->regval = ((((dfr >> ID_AA64DFR0_EL1_WRPs_SHIFT) & 0xf) << 28) | -- cgit v1.2.3 From 5a23e5c7cb0d5b2b38c33417579cd628be7d14c5 Mon Sep 17 00:00:00 2001 From: Oliver Upton Date: Wed, 4 Oct 2023 17:03:17 +0000 Subject: KVM: arm64: Advertise selected DebugVer in DBGDIDR.Version Much like we do for other fields, extract the Debug architecture version from the ID register to populate the corresponding field in DBGDIDR. Rewrite the existing sysreg field extractors to use SYS_FIELD_GET() for consistency. Suggested-by: Marc Zyngier Signed-off-by: Oliver Upton --- arch/arm64/kvm/sys_regs.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-) (limited to 'arch/arm64') diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c index b73f9ff0899b..34f578d110a9 100644 --- a/arch/arm64/kvm/sys_regs.c +++ b/arch/arm64/kvm/sys_regs.c @@ -2447,12 +2447,13 @@ static bool trap_dbgdidr(struct kvm_vcpu *vcpu, } else { u64 dfr = IDREG(vcpu->kvm, SYS_ID_AA64DFR0_EL1); u64 pfr = IDREG(vcpu->kvm, SYS_ID_AA64PFR0_EL1); - u32 el3 = !!cpuid_feature_extract_unsigned_field(pfr, ID_AA64PFR0_EL1_EL3_SHIFT); + u32 el3 = !!SYS_FIELD_GET(ID_AA64PFR0_EL1, EL3, pfr); - p->regval = ((((dfr >> ID_AA64DFR0_EL1_WRPs_SHIFT) & 0xf) << 28) | - (((dfr >> ID_AA64DFR0_EL1_BRPs_SHIFT) & 0xf) << 24) | - (((dfr >> ID_AA64DFR0_EL1_CTX_CMPs_SHIFT) & 0xf) << 20) - | (6 << 16) | (1 << 15) | (el3 << 14) | (el3 << 12)); + p->regval = ((SYS_FIELD_GET(ID_AA64DFR0_EL1, WRPs, dfr) << 28) | + (SYS_FIELD_GET(ID_AA64DFR0_EL1, BRPs, dfr) << 24) | + (SYS_FIELD_GET(ID_AA64DFR0_EL1, CTX_CMPs, dfr) << 20) | + (SYS_FIELD_GET(ID_AA64DFR0_EL1, DebugVer, dfr) << 16) | + (1 << 15) | (el3 << 14) | (el3 << 12)); return true; } } -- cgit v1.2.3 From a9bc4a1c1e0c206838bc2d0c8621ca6df9704a2f Mon Sep 17 00:00:00 2001 From: Oliver Upton Date: Tue, 3 Oct 2023 23:04:00 +0000 Subject: KVM: arm64: Reject attempts to set invalid debug arch version The debug architecture is mandatory in ARMv8, so KVM should not allow userspace to configure a vCPU with less than that. Of course, this isn't handled elegantly by the generic ID register plumbing, as the respective ID register fields have a nonzero starting value. Add an explicit check for debug versions less than v8 of the architecture. Reviewed-by: Marc Zyngier Link: https://lore.kernel.org/r/20231003230408.3405722-5-oliver.upton@linux.dev Signed-off-by: Oliver Upton --- arch/arm64/kvm/sys_regs.c | 32 +++++++++++++++++++++++++++++--- 1 file changed, 29 insertions(+), 3 deletions(-) (limited to 'arch/arm64') diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c index 34f578d110a9..1178e2690b77 100644 --- a/arch/arm64/kvm/sys_regs.c +++ b/arch/arm64/kvm/sys_regs.c @@ -1216,8 +1216,14 @@ static s64 kvm_arm64_ftr_safe_value(u32 id, const struct arm64_ftr_bits *ftrp, /* Some features have different safe value type in KVM than host features */ switch (id) { case SYS_ID_AA64DFR0_EL1: - if (kvm_ftr.shift == ID_AA64DFR0_EL1_PMUVer_SHIFT) + switch (kvm_ftr.shift) { + case ID_AA64DFR0_EL1_PMUVer_SHIFT: kvm_ftr.type = FTR_LOWER_SAFE; + break; + case ID_AA64DFR0_EL1_DebugVer_SHIFT: + kvm_ftr.type = FTR_LOWER_SAFE; + break; + } break; case SYS_ID_DFR0_EL1: if (kvm_ftr.shift == ID_DFR0_EL1_PerfMon_SHIFT) @@ -1476,14 +1482,22 @@ static u64 read_sanitised_id_aa64pfr0_el1(struct kvm_vcpu *vcpu, return val; } +#define ID_REG_LIMIT_FIELD_ENUM(val, reg, field, limit) \ +({ \ + u64 __f_val = FIELD_GET(reg##_##field##_MASK, val); \ + (val) &= ~reg##_##field##_MASK; \ + (val) |= FIELD_PREP(reg##_##field##_MASK, \ + min(__f_val, (u64)reg##_##field##_##limit)); \ + (val); \ +}) + static u64 read_sanitised_id_aa64dfr0_el1(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd) { u64 val = read_sanitised_ftr_reg(SYS_ID_AA64DFR0_EL1); /* Limit debug to ARMv8.0 */ - val &= ~ID_AA64DFR0_EL1_DebugVer_MASK; - val |= SYS_FIELD_PREP_ENUM(ID_AA64DFR0_EL1, DebugVer, IMP); + val = ID_REG_LIMIT_FIELD_ENUM(val, ID_AA64DFR0_EL1, DebugVer, IMP); /* * Only initialize the PMU version if the vCPU was configured with one. @@ -1503,6 +1517,7 @@ static int set_id_aa64dfr0_el1(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd, u64 val) { + u8 debugver = SYS_FIELD_GET(ID_AA64DFR0_EL1, DebugVer, val); u8 pmuver = SYS_FIELD_GET(ID_AA64DFR0_EL1, PMUVer, val); /* @@ -1522,6 +1537,13 @@ static int set_id_aa64dfr0_el1(struct kvm_vcpu *vcpu, if (pmuver == ID_AA64DFR0_EL1_PMUVer_IMP_DEF) val &= ~ID_AA64DFR0_EL1_PMUVer_MASK; + /* + * ID_AA64DFR0_EL1.DebugVer is one of those awkward fields with a + * nonzero minimum safe value. + */ + if (debugver < ID_AA64DFR0_EL1_DebugVer_IMP) + return -EINVAL; + return set_id_reg(vcpu, rd, val); } @@ -1543,6 +1565,7 @@ static int set_id_dfr0_el1(struct kvm_vcpu *vcpu, u64 val) { u8 perfmon = SYS_FIELD_GET(ID_DFR0_EL1, PerfMon, val); + u8 copdbg = SYS_FIELD_GET(ID_DFR0_EL1, CopDbg, val); if (perfmon == ID_DFR0_EL1_PerfMon_IMPDEF) { val &= ~ID_DFR0_EL1_PerfMon_MASK; @@ -1558,6 +1581,9 @@ static int set_id_dfr0_el1(struct kvm_vcpu *vcpu, if (perfmon != 0 && perfmon < ID_DFR0_EL1_PerfMon_PMUv3) return -EINVAL; + if (copdbg < ID_DFR0_EL1_CopDbg_Armv8) + return -EINVAL; + return set_id_reg(vcpu, rd, val); } -- cgit v1.2.3 From 9f9917bc71b08335819ea667d1e392424fb76450 Mon Sep 17 00:00:00 2001 From: Oliver Upton Date: Tue, 3 Oct 2023 23:04:01 +0000 Subject: KVM: arm64: Bump up the default KVM sanitised debug version to v8p8 Since ID_AA64DFR0_EL1 and ID_DFR0_EL1 are now writable from userspace, it is safe to bump up the default KVM sanitised debug version to v8p8. Reviewed-by: Marc Zyngier Link: https://lore.kernel.org/r/20231003230408.3405722-6-oliver.upton@linux.dev Signed-off-by: Oliver Upton --- arch/arm64/kvm/sys_regs.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-) (limited to 'arch/arm64') diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c index 1178e2690b77..c28d864a6807 100644 --- a/arch/arm64/kvm/sys_regs.c +++ b/arch/arm64/kvm/sys_regs.c @@ -1496,8 +1496,7 @@ static u64 read_sanitised_id_aa64dfr0_el1(struct kvm_vcpu *vcpu, { u64 val = read_sanitised_ftr_reg(SYS_ID_AA64DFR0_EL1); - /* Limit debug to ARMv8.0 */ - val = ID_REG_LIMIT_FIELD_ENUM(val, ID_AA64DFR0_EL1, DebugVer, IMP); + val = ID_REG_LIMIT_FIELD_ENUM(val, ID_AA64DFR0_EL1, DebugVer, V8P8); /* * Only initialize the PMU version if the vCPU was configured with one. @@ -1557,6 +1556,8 @@ static u64 read_sanitised_id_dfr0_el1(struct kvm_vcpu *vcpu, if (kvm_vcpu_has_pmu(vcpu)) val |= SYS_FIELD_PREP(ID_DFR0_EL1, PerfMon, perfmon); + val = ID_REG_LIMIT_FIELD_ENUM(val, ID_DFR0_EL1, CopDbg, Debugv8p8); + return val; } @@ -2013,7 +2014,8 @@ static const struct sys_reg_desc sys_reg_descs[] = { .set_user = set_id_dfr0_el1, .visibility = aa32_id_visibility, .reset = read_sanitised_id_dfr0_el1, - .val = ID_DFR0_EL1_PerfMon_MASK, }, + .val = ID_DFR0_EL1_PerfMon_MASK | + ID_DFR0_EL1_CopDbg_MASK, }, ID_HIDDEN(ID_AFR0_EL1), AA32_ID_SANITISED(ID_MMFR0_EL1), AA32_ID_SANITISED(ID_MMFR1_EL1), @@ -2062,7 +2064,8 @@ static const struct sys_reg_desc sys_reg_descs[] = { .get_user = get_id_reg, .set_user = set_id_aa64dfr0_el1, .reset = read_sanitised_id_aa64dfr0_el1, - .val = ID_AA64DFR0_EL1_PMUVer_MASK, }, + .val = ID_AA64DFR0_EL1_PMUVer_MASK | + ID_AA64DFR0_EL1_DebugVer_MASK, }, ID_SANITISED(ID_AA64DFR1_EL1), ID_UNALLOCATED(5,2), ID_UNALLOCATED(5,3), -- cgit v1.2.3 From 56d77aa8bdf527f3b767fa27a3f135769151c92d Mon Sep 17 00:00:00 2001 From: Oliver Upton Date: Tue, 3 Oct 2023 23:04:02 +0000 Subject: KVM: arm64: Allow userspace to change ID_AA64ISAR{0-2}_EL1 Almost all of the features described by the ISA registers have no KVM involvement. Allow userspace to change the value of these registers with a couple exceptions: - MOPS is not writable as KVM does not currently virtualize FEAT_MOPS. - The PAuth fields are not writable as KVM requires both address and generic authentication be enabled. Co-developed-by: Jing Zhang Signed-off-by: Jing Zhang Reviewed-by: Marc Zyngier Link: https://lore.kernel.org/r/20231003230408.3405722-7-oliver.upton@linux.dev Signed-off-by: Oliver Upton --- arch/arm64/kvm/sys_regs.c | 38 ++++++++++++++++++++++++++------------ 1 file changed, 26 insertions(+), 12 deletions(-) (limited to 'arch/arm64') diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c index c28d864a6807..5d1a94af42f2 100644 --- a/arch/arm64/kvm/sys_regs.c +++ b/arch/arm64/kvm/sys_regs.c @@ -1851,11 +1851,14 @@ static unsigned int elx2_visibility(const struct kvm_vcpu *vcpu, * from userspace. */ -/* sys_reg_desc initialiser for known cpufeature ID registers */ -#define ID_SANITISED(name) { \ +#define ID_DESC(name) \ SYS_DESC(SYS_##name), \ .access = access_id_reg, \ - .get_user = get_id_reg, \ + .get_user = get_id_reg \ + +/* sys_reg_desc initialiser for known cpufeature ID registers */ +#define ID_SANITISED(name) { \ + ID_DESC(name), \ .set_user = set_id_reg, \ .visibility = id_visibility, \ .reset = kvm_read_sanitised_id_reg, \ @@ -1864,15 +1867,22 @@ static unsigned int elx2_visibility(const struct kvm_vcpu *vcpu, /* 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, \ + ID_DESC(name), \ .set_user = set_id_reg, \ .visibility = aa32_id_visibility, \ .reset = kvm_read_sanitised_id_reg, \ .val = 0, \ } +/* sys_reg_desc initialiser for writable ID registers */ +#define ID_WRITABLE(name, mask) { \ + ID_DESC(name), \ + .set_user = set_id_reg, \ + .visibility = id_visibility, \ + .reset = kvm_read_sanitised_id_reg, \ + .val = mask, \ +} + /* * sys_reg_desc initialiser for architecturally unallocated cpufeature ID * register with encoding Op0=3, Op1=0, CRn=0, CRm=crm, Op2=op2 @@ -1894,9 +1904,7 @@ static unsigned int elx2_visibility(const struct kvm_vcpu *vcpu, * RAZ for the guest. */ #define ID_HIDDEN(name) { \ - SYS_DESC(SYS_##name), \ - .access = access_id_reg, \ - .get_user = get_id_reg, \ + ID_DESC(name), \ .set_user = set_id_reg, \ .visibility = raz_visibility, \ .reset = kvm_read_sanitised_id_reg, \ @@ -2075,9 +2083,15 @@ static const struct sys_reg_desc sys_reg_descs[] = { ID_UNALLOCATED(5,7), /* CRm=6 */ - ID_SANITISED(ID_AA64ISAR0_EL1), - ID_SANITISED(ID_AA64ISAR1_EL1), - ID_SANITISED(ID_AA64ISAR2_EL1), + ID_WRITABLE(ID_AA64ISAR0_EL1, ~ID_AA64ISAR0_EL1_RES0), + ID_WRITABLE(ID_AA64ISAR1_EL1, ~(ID_AA64ISAR1_EL1_GPI | + ID_AA64ISAR1_EL1_GPA | + ID_AA64ISAR1_EL1_API | + ID_AA64ISAR1_EL1_APA)), + ID_WRITABLE(ID_AA64ISAR2_EL1, ~(ID_AA64ISAR2_EL1_RES0 | + ID_AA64ISAR2_EL1_MOPS | + ID_AA64ISAR2_EL1_APA3 | + ID_AA64ISAR2_EL1_GPA3)), ID_UNALLOCATED(6,3), ID_UNALLOCATED(6,4), ID_UNALLOCATED(6,5), -- cgit v1.2.3 From d5a32b60dc184cc7309f83648a368b94d91c797f Mon Sep 17 00:00:00 2001 From: Jing Zhang Date: Tue, 3 Oct 2023 23:04:03 +0000 Subject: KVM: arm64: Allow userspace to change ID_AA64MMFR{0-2}_EL1 Allow userspace to modify the guest-visible values of these ID registers. Prevent changes to any of the virtualization features until KVM picks up support for nested and we have a handle on managing NV features. Signed-off-by: Jing Zhang [oliver: prevent changes to EL2 features for now] Reviewed-by: Marc Zyngier Link: https://lore.kernel.org/r/20231003230408.3405722-8-oliver.upton@linux.dev Signed-off-by: Oliver Upton --- arch/arm64/kvm/sys_regs.c | 20 +++++++++++++++++--- 1 file changed, 17 insertions(+), 3 deletions(-) (limited to 'arch/arm64') diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c index 5d1a94af42f2..d850b05eb504 100644 --- a/arch/arm64/kvm/sys_regs.c +++ b/arch/arm64/kvm/sys_regs.c @@ -2099,9 +2099,23 @@ static const struct sys_reg_desc sys_reg_descs[] = { ID_UNALLOCATED(6,7), /* CRm=7 */ - ID_SANITISED(ID_AA64MMFR0_EL1), - ID_SANITISED(ID_AA64MMFR1_EL1), - ID_SANITISED(ID_AA64MMFR2_EL1), + ID_WRITABLE(ID_AA64MMFR0_EL1, ~(ID_AA64MMFR0_EL1_RES0 | + ID_AA64MMFR0_EL1_TGRAN4_2 | + ID_AA64MMFR0_EL1_TGRAN64_2 | + ID_AA64MMFR0_EL1_TGRAN16_2)), + ID_WRITABLE(ID_AA64MMFR1_EL1, ~(ID_AA64MMFR1_EL1_RES0 | + ID_AA64MMFR1_EL1_HCX | + ID_AA64MMFR1_EL1_XNX | + ID_AA64MMFR1_EL1_TWED | + ID_AA64MMFR1_EL1_XNX | + ID_AA64MMFR1_EL1_VH | + ID_AA64MMFR1_EL1_VMIDBits)), + ID_WRITABLE(ID_AA64MMFR2_EL1, ~(ID_AA64MMFR2_EL1_RES0 | + ID_AA64MMFR2_EL1_EVT | + ID_AA64MMFR2_EL1_FWB | + ID_AA64MMFR2_EL1_IDS | + ID_AA64MMFR2_EL1_NV | + ID_AA64MMFR2_EL1_CCIDX)), ID_SANITISED(ID_AA64MMFR3_EL1), ID_UNALLOCATED(7,4), ID_UNALLOCATED(7,5), -- cgit v1.2.3 From 8cfd5be88ebe3d71be1a2c52fc72a355bb924b49 Mon Sep 17 00:00:00 2001 From: Jing Zhang Date: Tue, 3 Oct 2023 23:04:04 +0000 Subject: KVM: arm64: Allow userspace to change ID_AA64PFR0_EL1 Allow userspace to change the guest-visible value of the register with some severe limitation: - No changes to features not virtualized by KVM (AMU, MPAM, RAS) - Short of full GICv2 emulation in kernel, hiding GICv3 from the guest makes absolutely no sense. - FP is effectively assumed for KVM VMs. Signed-off-by: Jing Zhang [oliver: restrict features that are illogical to change] Reviewed-by: Marc Zyngier Link: https://lore.kernel.org/r/20231003230408.3405722-9-oliver.upton@linux.dev Signed-off-by: Oliver Upton --- arch/arm64/kvm/sys_regs.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) (limited to 'arch/arm64') diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c index d850b05eb504..dbf915f88b17 100644 --- a/arch/arm64/kvm/sys_regs.c +++ b/arch/arm64/kvm/sys_regs.c @@ -2057,7 +2057,13 @@ static const struct sys_reg_desc sys_reg_descs[] = { .get_user = get_id_reg, .set_user = set_id_reg, .reset = read_sanitised_id_aa64pfr0_el1, - .val = ID_AA64PFR0_EL1_CSV2_MASK | ID_AA64PFR0_EL1_CSV3_MASK, }, + .val = ~(ID_AA64PFR0_EL1_AMU | + ID_AA64PFR0_EL1_MPAM | + ID_AA64PFR0_EL1_SVE | + ID_AA64PFR0_EL1_RAS | + ID_AA64PFR0_EL1_GIC | + ID_AA64PFR0_EL1_AdvSIMD | + ID_AA64PFR0_EL1_FP), }, ID_SANITISED(ID_AA64PFR1_EL1), ID_UNALLOCATED(4,2), ID_UNALLOCATED(4,3), -- cgit v1.2.3 From f89fbb350dd76d6b5f080954309b9dec5ad220ac Mon Sep 17 00:00:00 2001 From: Oliver Upton Date: Tue, 3 Oct 2023 23:04:05 +0000 Subject: KVM: arm64: Allow userspace to change ID_AA64ZFR0_EL1 All known fields in ID_AA64ZFR0_EL1 describe the unprivileged instructions supported by the PE's SVE implementation. Allow userspace to pick and choose the advertised feature set, though nothing stops the guest from using undisclosed instructions. Reviewed-by: Marc Zyngier Link: https://lore.kernel.org/r/20231003230408.3405722-10-oliver.upton@linux.dev Signed-off-by: Oliver Upton --- arch/arm64/kvm/sys_regs.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'arch/arm64') diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c index dbf915f88b17..57c8190d5438 100644 --- a/arch/arm64/kvm/sys_regs.c +++ b/arch/arm64/kvm/sys_regs.c @@ -2067,7 +2067,7 @@ static const struct sys_reg_desc sys_reg_descs[] = { ID_SANITISED(ID_AA64PFR1_EL1), ID_UNALLOCATED(4,2), ID_UNALLOCATED(4,3), - ID_SANITISED(ID_AA64ZFR0_EL1), + ID_WRITABLE(ID_AA64ZFR0_EL1, ~ID_AA64ZFR0_EL1_RES0), ID_HIDDEN(ID_AA64SMFR0_EL1), ID_UNALLOCATED(4,6), ID_UNALLOCATED(4,7), -- cgit v1.2.3