* [PATCH v5 0/6] Support writable CPU ID registers from userspace
@ 2023-04-02 18:37 Jing Zhang
2023-04-02 18:37 ` [PATCH v5 1/6] KVM: arm64: Move CPU ID feature registers emulation into a separate file Jing Zhang
` (6 more replies)
0 siblings, 7 replies; 13+ messages in thread
From: Jing Zhang @ 2023-04-02 18:37 UTC (permalink / raw)
To: KVM, KVMARM, ARMLinux, Marc Zyngier, Oliver Upton
Cc: Will Deacon, Paolo Bonzini, James Morse, Alexandru Elisei,
Suzuki K Poulose, Fuad Tabba, Reiji Watanabe,
Raghavendra Rao Ananta, Jing Zhang
This patchset refactors/adds code to support writable per guest CPU ID feature
registers. Part of the code/ideas are from
https://lore.kernel.org/all/20220419065544.3616948-1-reijiw@google.com .
No functional change is intended in this patchset. With the new CPU ID feature
registers infrastructure, only writtings of ID_AA64PFR0_EL1.[CSV2|CSV3],
ID_AA64DFR0_EL1.PMUVer and ID_DFR0_ELF.PerfMon are allowed as KVM does before.
Writable (Configurable) per guest CPU ID feature registers are useful for
creating/migrating guest on ARM CPUs with different kinds of features.
---
* v4 -> v5
- Rebased to 2fad20ae05cb (kvmarm/next)
Merge branch kvm-arm64/selftest/misc-6,4 into kvmarm-master/next
- Use kvm->arch.config_lock to guard update to multiple VM scope idregs
to avoid lock inversion
- Add back IDREG() macro for idregs access
- Refactor struct id_reg_desc by using existing infrastructure.
- Addressed many other comments from Marc.
* v3 -> v4
- Remove IDREG() macro for ID reg access, use simple array access instead
- Rename kvm_arm_read_id_reg_with_encoding() to kvm_arm_read_id_reg()
- Save perfmon value in ID_DFR0_EL1 instead of pmuver
- Update perfmon in ID_DFR0_EL1 and pmuver in ID_AA64DFR0_EL1 atomically
- Remove kvm_vcpu_has_pmu() in macro kvm_pmu_is_3p5()
- Improve ID register sanity checking in kvm_arm_check_idreg_table()
* v2 -> v3
- Rebased to 96a4627dbbd4 (kvmarm/next)
Merge tag ' https://github.com/oupton/linux tags/kvmarm-6.3' from into kvmarm-master/next
- Add id registere emulation entry point function emulate_id_reg
- Fix consistency for ID_AA64DFR0_EL1.PMUVer and ID_DFR0_EL1.PerfMon
- Improve the checking for id register table by ensuring that every entry has
the correct id register encoding.
- Addressed other comments from Reiji and Marc.
* v1 -> v2
- Rebase to 7121a2e1d107 (kvmarm/next) Merge branch kvm-arm64/nv-prefix into kvmarm/next
- Address writing issue for PMUVer
[1] https://lore.kernel.org/all/20230201025048.205820-1-jingzhangos@google.com
[2] https://lore.kernel.org/all/20230212215830.2975485-1-jingzhangos@google.com
[3] https://lore.kernel.org/all/20230228062246.1222387-1-jingzhangos@google.com
[4] https://lore.kernel.org/all/20230317050637.766317-1-jingzhangos@google.com
---
Jing Zhang (6):
KVM: arm64: Move CPU ID feature registers emulation into a separate
file
KVM: arm64: Save ID registers' sanitized value per guest
KVM: arm64: Use per guest ID register for ID_AA64PFR0_EL1.[CSV2|CSV3]
KVM: arm64: Use per guest ID register for ID_AA64DFR0_EL1.PMUVer
KVM: arm64: Introduce ID register specific descriptor
KVM: arm64: Refactor writings for PMUVer/CSV2/CSV3
arch/arm64/include/asm/cpufeature.h | 5 +
arch/arm64/include/asm/kvm_host.h | 34 +-
arch/arm64/kernel/cpufeature.c | 8 +-
arch/arm64/kvm/Makefile | 2 +-
arch/arm64/kvm/arm.c | 24 +-
arch/arm64/kvm/hyp/nvhe/sys_regs.c | 7 -
arch/arm64/kvm/id_regs.c | 790 ++++++++++++++++++++++++++++
arch/arm64/kvm/sys_regs.c | 466 ++--------------
arch/arm64/kvm/sys_regs.h | 29 +
include/kvm/arm_pmu.h | 5 +-
10 files changed, 897 insertions(+), 473 deletions(-)
create mode 100644 arch/arm64/kvm/id_regs.c
base-commit: 2fad20ae05cbcbd1a34272ddd8e27975b4ddcabf
--
2.40.0.348.gf938b09366-goog
^ permalink raw reply [flat|nested] 13+ messages in thread
* [PATCH v5 1/6] KVM: arm64: Move CPU ID feature registers emulation into a separate file
2023-04-02 18:37 [PATCH v5 0/6] Support writable CPU ID registers from userspace Jing Zhang
@ 2023-04-02 18:37 ` Jing Zhang
2023-04-02 18:37 ` [PATCH v5 2/6] KVM: arm64: Save ID registers' sanitized value per guest Jing Zhang
` (5 subsequent siblings)
6 siblings, 0 replies; 13+ messages in thread
From: Jing Zhang @ 2023-04-02 18:37 UTC (permalink / raw)
To: KVM, KVMARM, ARMLinux, Marc Zyngier, Oliver Upton
Cc: Will Deacon, Paolo Bonzini, James Morse, Alexandru Elisei,
Suzuki K Poulose, Fuad Tabba, Reiji Watanabe,
Raghavendra Rao Ananta, Jing Zhang
Create a new file id_regs.c for CPU ID feature registers emulation code,
which are moved from sys_regs.c and tweak sys_regs code accordingly.
No functional change intended.
Signed-off-by: Jing Zhang <jingzhangos@google.com>
---
arch/arm64/kvm/Makefile | 2 +-
arch/arm64/kvm/id_regs.c | 496 ++++++++++++++++++++++++++++++++++++++
arch/arm64/kvm/sys_regs.c | 461 +++--------------------------------
arch/arm64/kvm/sys_regs.h | 27 +++
4 files changed, 559 insertions(+), 427 deletions(-)
create mode 100644 arch/arm64/kvm/id_regs.c
diff --git a/arch/arm64/kvm/Makefile b/arch/arm64/kvm/Makefile
index c0c050e53157..a6a315fcd81e 100644
--- a/arch/arm64/kvm/Makefile
+++ b/arch/arm64/kvm/Makefile
@@ -13,7 +13,7 @@ obj-$(CONFIG_KVM) += hyp/
kvm-y += arm.o mmu.o mmio.o psci.o hypercalls.o pvtime.o \
inject_fault.o va_layout.o handle_exit.o \
guest.o debug.o reset.o sys_regs.o stacktrace.o \
- vgic-sys-reg-v3.o fpsimd.o pkvm.o \
+ vgic-sys-reg-v3.o fpsimd.o pkvm.o id_regs.o \
arch_timer.o trng.o vmid.o emulate-nested.o nested.o \
vgic/vgic.o vgic/vgic-init.o \
vgic/vgic-irqfd.o vgic/vgic-v2.o \
diff --git a/arch/arm64/kvm/id_regs.c b/arch/arm64/kvm/id_regs.c
new file mode 100644
index 000000000000..638c0f8e4cd2
--- /dev/null
+++ b/arch/arm64/kvm/id_regs.c
@@ -0,0 +1,496 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2023 - Google LLC
+ * Author: Jing Zhang <jingzhangos@google.com>
+ *
+ * Moved from arch/arm64/kvm/sys_regs.c
+ * Copyright (C) 2012,2013 - ARM Ltd
+ * Author: Marc Zyngier <marc.zyngier@arm.com>
+ */
+
+#include <linux/bitfield.h>
+#include <linux/bsearch.h>
+#include <linux/kvm_host.h>
+#include <asm/kvm_emulate.h>
+#include <asm/sysreg.h>
+#include <asm/cpufeature.h>
+#include <asm/kvm_nested.h>
+
+#include "sys_regs.h"
+
+static u8 vcpu_pmuver(const struct kvm_vcpu *vcpu)
+{
+ if (kvm_vcpu_has_pmu(vcpu))
+ return vcpu->kvm->arch.dfr0_pmuver.imp;
+
+ return vcpu->kvm->arch.dfr0_pmuver.unimp;
+}
+
+static u8 perfmon_to_pmuver(u8 perfmon)
+{
+ switch (perfmon) {
+ case ID_DFR0_EL1_PerfMon_PMUv3:
+ return ID_AA64DFR0_EL1_PMUVer_IMP;
+ case ID_DFR0_EL1_PerfMon_IMPDEF:
+ return ID_AA64DFR0_EL1_PMUVer_IMP_DEF;
+ default:
+ /* Anything ARMv8.1+ and NI have the same value. For now. */
+ return perfmon;
+ }
+}
+
+static u8 pmuver_to_perfmon(u8 pmuver)
+{
+ switch (pmuver) {
+ case ID_AA64DFR0_EL1_PMUVer_IMP:
+ return ID_DFR0_EL1_PerfMon_PMUv3;
+ case ID_AA64DFR0_EL1_PMUVer_IMP_DEF:
+ return ID_DFR0_EL1_PerfMon_IMPDEF;
+ default:
+ /* Anything ARMv8.1+ and NI have the same value. For now. */
+ return pmuver;
+ }
+}
+
+/* Read a sanitised cpufeature ID register by sys_reg_desc */
+static u64 read_id_reg(const struct kvm_vcpu *vcpu, struct sys_reg_desc const *r)
+{
+ u32 id = reg_to_encoding(r);
+ u64 val;
+
+ if (sysreg_visible_as_raz(vcpu, r))
+ return 0;
+
+ val = read_sanitised_ftr_reg(id);
+
+ switch (id) {
+ case SYS_ID_AA64PFR0_EL1:
+ if (!vcpu_has_sve(vcpu))
+ val &= ~ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_SVE);
+ val &= ~ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_AMU);
+ val &= ~ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_CSV2);
+ val |= FIELD_PREP(ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_CSV2),
+ (u64)vcpu->kvm->arch.pfr0_csv2);
+ val &= ~ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_CSV3);
+ val |= FIELD_PREP(ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_CSV3),
+ (u64)vcpu->kvm->arch.pfr0_csv3);
+ if (kvm_vgic_global_state.type == VGIC_V3) {
+ val &= ~ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_GIC);
+ val |= FIELD_PREP(ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_GIC), 1);
+ }
+ break;
+ case SYS_ID_AA64PFR1_EL1:
+ if (!kvm_has_mte(vcpu->kvm))
+ val &= ~ARM64_FEATURE_MASK(ID_AA64PFR1_EL1_MTE);
+
+ val &= ~ARM64_FEATURE_MASK(ID_AA64PFR1_EL1_SME);
+ break;
+ case SYS_ID_AA64ISAR1_EL1:
+ if (!vcpu_has_ptrauth(vcpu))
+ val &= ~(ARM64_FEATURE_MASK(ID_AA64ISAR1_EL1_APA) |
+ ARM64_FEATURE_MASK(ID_AA64ISAR1_EL1_API) |
+ ARM64_FEATURE_MASK(ID_AA64ISAR1_EL1_GPA) |
+ ARM64_FEATURE_MASK(ID_AA64ISAR1_EL1_GPI));
+ break;
+ case SYS_ID_AA64ISAR2_EL1:
+ if (!vcpu_has_ptrauth(vcpu))
+ val &= ~(ARM64_FEATURE_MASK(ID_AA64ISAR2_EL1_APA3) |
+ ARM64_FEATURE_MASK(ID_AA64ISAR2_EL1_GPA3));
+ if (!cpus_have_final_cap(ARM64_HAS_WFXT))
+ val &= ~ARM64_FEATURE_MASK(ID_AA64ISAR2_EL1_WFxT);
+ break;
+ case SYS_ID_AA64DFR0_EL1:
+ /* Limit debug to ARMv8.0 */
+ val &= ~ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_DebugVer);
+ val |= FIELD_PREP(ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_DebugVer), 6);
+ /* Set PMUver to the required version */
+ val &= ~ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_PMUVer);
+ val |= FIELD_PREP(ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_PMUVer),
+ vcpu_pmuver(vcpu));
+ /* Hide SPE from guests */
+ val &= ~ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_PMSVer);
+ break;
+ case SYS_ID_DFR0_EL1:
+ val &= ~ARM64_FEATURE_MASK(ID_DFR0_EL1_PerfMon);
+ val |= FIELD_PREP(ARM64_FEATURE_MASK(ID_DFR0_EL1_PerfMon),
+ pmuver_to_perfmon(vcpu_pmuver(vcpu)));
+ break;
+ case SYS_ID_AA64MMFR2_EL1:
+ val &= ~ID_AA64MMFR2_EL1_CCIDX_MASK;
+ break;
+ case SYS_ID_MMFR4_EL1:
+ val &= ~ARM64_FEATURE_MASK(ID_MMFR4_EL1_CCIDX);
+ break;
+ }
+
+ return val;
+}
+
+/* cpufeature ID register access trap handlers */
+
+static bool access_id_reg(struct kvm_vcpu *vcpu,
+ struct sys_reg_params *p,
+ const struct sys_reg_desc *r)
+{
+ if (p->is_write)
+ return write_to_read_only(vcpu, p, r);
+
+ p->regval = read_id_reg(vcpu, r);
+ if (vcpu_has_nv(vcpu))
+ access_nested_id_reg(vcpu, p, r);
+
+ return true;
+}
+
+/*
+ * cpufeature ID register user accessors
+ *
+ * For now, these registers are immutable for userspace, so no values
+ * are stored, and for set_id_reg() we don't allow the effective value
+ * to be changed.
+ */
+static int get_id_reg(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
+ u64 *val)
+{
+ *val = read_id_reg(vcpu, rd);
+ return 0;
+}
+
+static int set_id_reg(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
+ u64 val)
+{
+ /* This is what we mean by invariant: you can't change it. */
+ if (val != read_id_reg(vcpu, rd))
+ return -EINVAL;
+
+ return 0;
+}
+
+static unsigned int id_visibility(const struct kvm_vcpu *vcpu,
+ const struct sys_reg_desc *r)
+{
+ u32 id = reg_to_encoding(r);
+
+ switch (id) {
+ case SYS_ID_AA64ZFR0_EL1:
+ if (!vcpu_has_sve(vcpu))
+ return REG_RAZ;
+ break;
+ }
+
+ return 0;
+}
+
+static unsigned int aa32_id_visibility(const struct kvm_vcpu *vcpu,
+ const struct sys_reg_desc *r)
+{
+ /*
+ * AArch32 ID registers are UNKNOWN if AArch32 isn't implemented at any
+ * EL. Promote to RAZ/WI in order to guarantee consistency between
+ * systems.
+ */
+ if (!kvm_supports_32bit_el0())
+ return REG_RAZ | REG_USER_WI;
+
+ return id_visibility(vcpu, r);
+}
+
+static int set_id_aa64pfr0_el1(struct kvm_vcpu *vcpu,
+ const struct sys_reg_desc *rd,
+ u64 val)
+{
+ u8 csv2, csv3;
+
+ /*
+ * Allow AA64PFR0_EL1.CSV2 to be set from userspace as long as
+ * it doesn't promise more than what is actually provided (the
+ * guest could otherwise be covered in ectoplasmic residue).
+ */
+ csv2 = cpuid_feature_extract_unsigned_field(val, ID_AA64PFR0_EL1_CSV2_SHIFT);
+ if (csv2 > 1 ||
+ (csv2 && arm64_get_spectre_v2_state() != SPECTRE_UNAFFECTED))
+ return -EINVAL;
+
+ /* Same thing for CSV3 */
+ csv3 = cpuid_feature_extract_unsigned_field(val, ID_AA64PFR0_EL1_CSV3_SHIFT);
+ if (csv3 > 1 ||
+ (csv3 && arm64_get_meltdown_state() != SPECTRE_UNAFFECTED))
+ return -EINVAL;
+
+ /* We can only differ with CSV[23], and anything else is an error */
+ val ^= read_id_reg(vcpu, rd);
+ val &= ~(ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_CSV2) |
+ ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_CSV3));
+ if (val)
+ return -EINVAL;
+
+ vcpu->kvm->arch.pfr0_csv2 = csv2;
+ vcpu->kvm->arch.pfr0_csv3 = csv3;
+
+ return 0;
+}
+
+static int set_id_aa64dfr0_el1(struct kvm_vcpu *vcpu,
+ const struct sys_reg_desc *rd,
+ u64 val)
+{
+ u8 pmuver, host_pmuver;
+ bool valid_pmu;
+
+ host_pmuver = kvm_arm_pmu_get_pmuver_limit();
+
+ /*
+ * Allow AA64DFR0_EL1.PMUver to be set from userspace as long
+ * as it doesn't promise more than what the HW gives us. We
+ * allow an IMPDEF PMU though, only if no PMU is supported
+ * (KVM backward compatibility handling).
+ */
+ pmuver = FIELD_GET(ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_PMUVer), val);
+ if ((pmuver != ID_AA64DFR0_EL1_PMUVer_IMP_DEF && pmuver > host_pmuver))
+ return -EINVAL;
+
+ valid_pmu = (pmuver != 0 && pmuver != ID_AA64DFR0_EL1_PMUVer_IMP_DEF);
+
+ /* Make sure view register and PMU support do match */
+ if (kvm_vcpu_has_pmu(vcpu) != valid_pmu)
+ return -EINVAL;
+
+ /* We can only differ with PMUver, and anything else is an error */
+ val ^= read_id_reg(vcpu, rd);
+ val &= ~ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_PMUVer);
+ if (val)
+ return -EINVAL;
+
+ if (valid_pmu)
+ vcpu->kvm->arch.dfr0_pmuver.imp = pmuver;
+ else
+ vcpu->kvm->arch.dfr0_pmuver.unimp = pmuver;
+
+ return 0;
+}
+
+static int set_id_dfr0_el1(struct kvm_vcpu *vcpu,
+ const struct sys_reg_desc *rd,
+ u64 val)
+{
+ u8 perfmon, host_perfmon;
+ bool valid_pmu;
+
+ host_perfmon = pmuver_to_perfmon(kvm_arm_pmu_get_pmuver_limit());
+
+ /*
+ * Allow DFR0_EL1.PerfMon to be set from userspace as long as
+ * it doesn't promise more than what the HW gives us on the
+ * AArch64 side (as everything is emulated with that), and
+ * that this is a PMUv3.
+ */
+ perfmon = FIELD_GET(ARM64_FEATURE_MASK(ID_DFR0_EL1_PerfMon), val);
+ if ((perfmon != ID_DFR0_EL1_PerfMon_IMPDEF && perfmon > host_perfmon) ||
+ (perfmon != 0 && perfmon < ID_DFR0_EL1_PerfMon_PMUv3))
+ return -EINVAL;
+
+ valid_pmu = (perfmon != 0 && perfmon != ID_DFR0_EL1_PerfMon_IMPDEF);
+
+ /* Make sure view register and PMU support do match */
+ if (kvm_vcpu_has_pmu(vcpu) != valid_pmu)
+ return -EINVAL;
+
+ /* We can only differ with PerfMon, and anything else is an error */
+ val ^= read_id_reg(vcpu, rd);
+ val &= ~ARM64_FEATURE_MASK(ID_DFR0_EL1_PerfMon);
+ if (val)
+ return -EINVAL;
+
+ if (valid_pmu)
+ vcpu->kvm->arch.dfr0_pmuver.imp = perfmon_to_pmuver(perfmon);
+ else
+ vcpu->kvm->arch.dfr0_pmuver.unimp = perfmon_to_pmuver(perfmon);
+
+ return 0;
+}
+
+/* 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, \
+}
+
+/* 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, \
+}
+
+/*
+ * sys_reg_desc initialiser for architecturally unallocated cpufeature ID
+ * 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 \
+}
+
+/*
+ * sys_reg_desc initialiser for known ID registers that we hide from guests.
+ * 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, \
+}
+
+static const struct sys_reg_desc id_reg_descs[] = {
+ /*
+ * ID regs: all ID_SANITISED() entries here must have corresponding
+ * entries in arm64_ftr_regs[].
+ */
+
+ /* AArch64 mappings of the AArch32 ID registers */
+ /* 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, },
+ ID_HIDDEN(ID_AFR0_EL1),
+ AA32_ID_SANITISED(ID_MMFR0_EL1),
+ AA32_ID_SANITISED(ID_MMFR1_EL1),
+ AA32_ID_SANITISED(ID_MMFR2_EL1),
+ AA32_ID_SANITISED(ID_MMFR3_EL1),
+
+ /* CRm=2 */
+ AA32_ID_SANITISED(ID_ISAR0_EL1),
+ AA32_ID_SANITISED(ID_ISAR1_EL1),
+ AA32_ID_SANITISED(ID_ISAR2_EL1),
+ AA32_ID_SANITISED(ID_ISAR3_EL1),
+ AA32_ID_SANITISED(ID_ISAR4_EL1),
+ AA32_ID_SANITISED(ID_ISAR5_EL1),
+ AA32_ID_SANITISED(ID_MMFR4_EL1),
+ AA32_ID_SANITISED(ID_ISAR6_EL1),
+
+ /* CRm=3 */
+ AA32_ID_SANITISED(MVFR0_EL1),
+ AA32_ID_SANITISED(MVFR1_EL1),
+ AA32_ID_SANITISED(MVFR2_EL1),
+ ID_UNALLOCATED(3, 3),
+ AA32_ID_SANITISED(ID_PFR2_EL1),
+ ID_HIDDEN(ID_DFR1_EL1),
+ AA32_ID_SANITISED(ID_MMFR5_EL1),
+ ID_UNALLOCATED(3, 7),
+
+ /* 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, },
+ ID_SANITISED(ID_AA64PFR1_EL1),
+ ID_UNALLOCATED(4, 2),
+ ID_UNALLOCATED(4, 3),
+ ID_SANITISED(ID_AA64ZFR0_EL1),
+ ID_HIDDEN(ID_AA64SMFR0_EL1),
+ ID_UNALLOCATED(4, 6),
+ 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, },
+ ID_SANITISED(ID_AA64DFR1_EL1),
+ ID_UNALLOCATED(5, 2),
+ ID_UNALLOCATED(5, 3),
+ ID_HIDDEN(ID_AA64AFR0_EL1),
+ ID_HIDDEN(ID_AA64AFR1_EL1),
+ ID_UNALLOCATED(5, 6),
+ ID_UNALLOCATED(5, 7),
+
+ /* CRm=6 */
+ ID_SANITISED(ID_AA64ISAR0_EL1),
+ ID_SANITISED(ID_AA64ISAR1_EL1),
+ ID_SANITISED(ID_AA64ISAR2_EL1),
+ ID_UNALLOCATED(6, 3),
+ ID_UNALLOCATED(6, 4),
+ ID_UNALLOCATED(6, 5),
+ ID_UNALLOCATED(6, 6),
+ ID_UNALLOCATED(6, 7),
+
+ /* CRm=7 */
+ ID_SANITISED(ID_AA64MMFR0_EL1),
+ ID_SANITISED(ID_AA64MMFR1_EL1),
+ ID_SANITISED(ID_AA64MMFR2_EL1),
+ ID_UNALLOCATED(7, 3),
+ ID_UNALLOCATED(7, 4),
+ ID_UNALLOCATED(7, 5),
+ ID_UNALLOCATED(7, 6),
+ ID_UNALLOCATED(7, 7),
+};
+
+/**
+ * emulate_id_reg - Emulate a guest access to an AArch64 CPU ID feature register
+ * @vcpu: The VCPU pointer
+ * @params: Decoded system register parameters
+ *
+ * Return: true if the ID register access was successful, false otherwise.
+ */
+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));
+
+ if (likely(r)) {
+ perform_access(vcpu, params, r);
+ } else {
+ print_sys_reg_msg(params,
+ "Unsupported guest id_reg access at: %lx [%08lx]\n",
+ *vcpu_pc(vcpu), *vcpu_cpsr(vcpu));
+ kvm_inject_undefined(vcpu);
+ }
+
+ return 1;
+}
+
+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));
+}
+
+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));
+}
+
+bool kvm_arm_check_idreg_table(void)
+{
+ return check_sysreg_table(id_reg_descs, ARRAY_SIZE(id_reg_descs), false);
+}
+
+int kvm_arm_walk_id_regs(struct kvm_vcpu *vcpu, u64 __user *uind)
+{
+ const struct sys_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);
+ if (err)
+ return err;
+ }
+ return total;
+}
diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index be7c2598e563..40be494391fd 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -53,9 +53,9 @@ static bool read_from_write_only(struct kvm_vcpu *vcpu,
return false;
}
-static bool write_to_read_only(struct kvm_vcpu *vcpu,
- struct sys_reg_params *params,
- const struct sys_reg_desc *r)
+bool write_to_read_only(struct kvm_vcpu *vcpu,
+ struct sys_reg_params *params,
+ const struct sys_reg_desc *r)
{
WARN_ONCE(1, "Unexpected sys_reg write to read-only register\n");
print_sys_reg_instr(params);
@@ -1159,163 +1159,11 @@ static bool access_arch_timer(struct kvm_vcpu *vcpu,
return true;
}
-static u8 vcpu_pmuver(const struct kvm_vcpu *vcpu)
-{
- if (kvm_vcpu_has_pmu(vcpu))
- return vcpu->kvm->arch.dfr0_pmuver.imp;
-
- return vcpu->kvm->arch.dfr0_pmuver.unimp;
-}
-
-static u8 perfmon_to_pmuver(u8 perfmon)
-{
- switch (perfmon) {
- case ID_DFR0_EL1_PerfMon_PMUv3:
- return ID_AA64DFR0_EL1_PMUVer_IMP;
- case ID_DFR0_EL1_PerfMon_IMPDEF:
- return ID_AA64DFR0_EL1_PMUVer_IMP_DEF;
- default:
- /* Anything ARMv8.1+ and NI have the same value. For now. */
- return perfmon;
- }
-}
-
-static u8 pmuver_to_perfmon(u8 pmuver)
-{
- switch (pmuver) {
- case ID_AA64DFR0_EL1_PMUVer_IMP:
- return ID_DFR0_EL1_PerfMon_PMUv3;
- case ID_AA64DFR0_EL1_PMUVer_IMP_DEF:
- return ID_DFR0_EL1_PerfMon_IMPDEF;
- default:
- /* Anything ARMv8.1+ and NI have the same value. For now. */
- return pmuver;
- }
-}
-
-/* Read a sanitised cpufeature ID register by sys_reg_desc */
-static u64 read_id_reg(const struct kvm_vcpu *vcpu, struct sys_reg_desc const *r)
-{
- u32 id = reg_to_encoding(r);
- u64 val;
-
- if (sysreg_visible_as_raz(vcpu, r))
- return 0;
-
- val = read_sanitised_ftr_reg(id);
-
- switch (id) {
- case SYS_ID_AA64PFR0_EL1:
- if (!vcpu_has_sve(vcpu))
- val &= ~ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_SVE);
- val &= ~ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_AMU);
- val &= ~ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_CSV2);
- val |= FIELD_PREP(ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_CSV2), (u64)vcpu->kvm->arch.pfr0_csv2);
- val &= ~ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_CSV3);
- val |= FIELD_PREP(ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_CSV3), (u64)vcpu->kvm->arch.pfr0_csv3);
- if (kvm_vgic_global_state.type == VGIC_V3) {
- val &= ~ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_GIC);
- val |= FIELD_PREP(ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_GIC), 1);
- }
- break;
- case SYS_ID_AA64PFR1_EL1:
- if (!kvm_has_mte(vcpu->kvm))
- val &= ~ARM64_FEATURE_MASK(ID_AA64PFR1_EL1_MTE);
-
- val &= ~ARM64_FEATURE_MASK(ID_AA64PFR1_EL1_SME);
- break;
- case SYS_ID_AA64ISAR1_EL1:
- if (!vcpu_has_ptrauth(vcpu))
- val &= ~(ARM64_FEATURE_MASK(ID_AA64ISAR1_EL1_APA) |
- ARM64_FEATURE_MASK(ID_AA64ISAR1_EL1_API) |
- ARM64_FEATURE_MASK(ID_AA64ISAR1_EL1_GPA) |
- ARM64_FEATURE_MASK(ID_AA64ISAR1_EL1_GPI));
- break;
- case SYS_ID_AA64ISAR2_EL1:
- if (!vcpu_has_ptrauth(vcpu))
- val &= ~(ARM64_FEATURE_MASK(ID_AA64ISAR2_EL1_APA3) |
- ARM64_FEATURE_MASK(ID_AA64ISAR2_EL1_GPA3));
- if (!cpus_have_final_cap(ARM64_HAS_WFXT))
- val &= ~ARM64_FEATURE_MASK(ID_AA64ISAR2_EL1_WFxT);
- break;
- case SYS_ID_AA64DFR0_EL1:
- /* Limit debug to ARMv8.0 */
- val &= ~ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_DebugVer);
- val |= FIELD_PREP(ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_DebugVer), 6);
- /* Set PMUver to the required version */
- val &= ~ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_PMUVer);
- val |= FIELD_PREP(ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_PMUVer),
- vcpu_pmuver(vcpu));
- /* Hide SPE from guests */
- val &= ~ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_PMSVer);
- break;
- case SYS_ID_DFR0_EL1:
- val &= ~ARM64_FEATURE_MASK(ID_DFR0_EL1_PerfMon);
- val |= FIELD_PREP(ARM64_FEATURE_MASK(ID_DFR0_EL1_PerfMon),
- pmuver_to_perfmon(vcpu_pmuver(vcpu)));
- break;
- case SYS_ID_AA64MMFR2_EL1:
- val &= ~ID_AA64MMFR2_EL1_CCIDX_MASK;
- break;
- case SYS_ID_MMFR4_EL1:
- val &= ~ARM64_FEATURE_MASK(ID_MMFR4_EL1_CCIDX);
- break;
- }
-
- return val;
-}
-
-static unsigned int id_visibility(const struct kvm_vcpu *vcpu,
- const struct sys_reg_desc *r)
-{
- u32 id = reg_to_encoding(r);
-
- switch (id) {
- case SYS_ID_AA64ZFR0_EL1:
- if (!vcpu_has_sve(vcpu))
- return REG_RAZ;
- break;
- }
-
- return 0;
-}
-
-static unsigned int aa32_id_visibility(const struct kvm_vcpu *vcpu,
- const struct sys_reg_desc *r)
-{
- /*
- * AArch32 ID registers are UNKNOWN if AArch32 isn't implemented at any
- * EL. Promote to RAZ/WI in order to guarantee consistency between
- * systems.
- */
- if (!kvm_supports_32bit_el0())
- return REG_RAZ | REG_USER_WI;
-
- return id_visibility(vcpu, r);
-}
-
-static unsigned int raz_visibility(const struct kvm_vcpu *vcpu,
- const struct sys_reg_desc *r)
+unsigned int raz_visibility(const struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
{
return REG_RAZ;
}
-/* cpufeature ID register access trap handlers */
-
-static bool access_id_reg(struct kvm_vcpu *vcpu,
- struct sys_reg_params *p,
- const struct sys_reg_desc *r)
-{
- if (p->is_write)
- return write_to_read_only(vcpu, p, r);
-
- p->regval = read_id_reg(vcpu, r);
- if (vcpu_has_nv(vcpu))
- access_nested_id_reg(vcpu, p, r);
-
- return true;
-}
-
/* Visibility overrides for SVE-specific control registers */
static unsigned int sve_visibility(const struct kvm_vcpu *vcpu,
const struct sys_reg_desc *rd)
@@ -1326,144 +1174,6 @@ static unsigned int sve_visibility(const struct kvm_vcpu *vcpu,
return REG_HIDDEN;
}
-static int set_id_aa64pfr0_el1(struct kvm_vcpu *vcpu,
- const struct sys_reg_desc *rd,
- u64 val)
-{
- u8 csv2, csv3;
-
- /*
- * Allow AA64PFR0_EL1.CSV2 to be set from userspace as long as
- * it doesn't promise more than what is actually provided (the
- * guest could otherwise be covered in ectoplasmic residue).
- */
- csv2 = cpuid_feature_extract_unsigned_field(val, ID_AA64PFR0_EL1_CSV2_SHIFT);
- if (csv2 > 1 ||
- (csv2 && arm64_get_spectre_v2_state() != SPECTRE_UNAFFECTED))
- return -EINVAL;
-
- /* Same thing for CSV3 */
- csv3 = cpuid_feature_extract_unsigned_field(val, ID_AA64PFR0_EL1_CSV3_SHIFT);
- if (csv3 > 1 ||
- (csv3 && arm64_get_meltdown_state() != SPECTRE_UNAFFECTED))
- return -EINVAL;
-
- /* We can only differ with CSV[23], and anything else is an error */
- val ^= read_id_reg(vcpu, rd);
- val &= ~(ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_CSV2) |
- ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_CSV3));
- if (val)
- return -EINVAL;
-
- vcpu->kvm->arch.pfr0_csv2 = csv2;
- vcpu->kvm->arch.pfr0_csv3 = csv3;
-
- return 0;
-}
-
-static int set_id_aa64dfr0_el1(struct kvm_vcpu *vcpu,
- const struct sys_reg_desc *rd,
- u64 val)
-{
- u8 pmuver, host_pmuver;
- bool valid_pmu;
-
- host_pmuver = kvm_arm_pmu_get_pmuver_limit();
-
- /*
- * Allow AA64DFR0_EL1.PMUver to be set from userspace as long
- * as it doesn't promise more than what the HW gives us. We
- * allow an IMPDEF PMU though, only if no PMU is supported
- * (KVM backward compatibility handling).
- */
- pmuver = FIELD_GET(ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_PMUVer), val);
- if ((pmuver != ID_AA64DFR0_EL1_PMUVer_IMP_DEF && pmuver > host_pmuver))
- return -EINVAL;
-
- valid_pmu = (pmuver != 0 && pmuver != ID_AA64DFR0_EL1_PMUVer_IMP_DEF);
-
- /* Make sure view register and PMU support do match */
- if (kvm_vcpu_has_pmu(vcpu) != valid_pmu)
- return -EINVAL;
-
- /* We can only differ with PMUver, and anything else is an error */
- val ^= read_id_reg(vcpu, rd);
- val &= ~ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_PMUVer);
- if (val)
- return -EINVAL;
-
- if (valid_pmu)
- vcpu->kvm->arch.dfr0_pmuver.imp = pmuver;
- else
- vcpu->kvm->arch.dfr0_pmuver.unimp = pmuver;
-
- return 0;
-}
-
-static int set_id_dfr0_el1(struct kvm_vcpu *vcpu,
- const struct sys_reg_desc *rd,
- u64 val)
-{
- u8 perfmon, host_perfmon;
- bool valid_pmu;
-
- host_perfmon = pmuver_to_perfmon(kvm_arm_pmu_get_pmuver_limit());
-
- /*
- * Allow DFR0_EL1.PerfMon to be set from userspace as long as
- * it doesn't promise more than what the HW gives us on the
- * AArch64 side (as everything is emulated with that), and
- * that this is a PMUv3.
- */
- perfmon = FIELD_GET(ARM64_FEATURE_MASK(ID_DFR0_EL1_PerfMon), val);
- if ((perfmon != ID_DFR0_EL1_PerfMon_IMPDEF && perfmon > host_perfmon) ||
- (perfmon != 0 && perfmon < ID_DFR0_EL1_PerfMon_PMUv3))
- return -EINVAL;
-
- valid_pmu = (perfmon != 0 && perfmon != ID_DFR0_EL1_PerfMon_IMPDEF);
-
- /* Make sure view register and PMU support do match */
- if (kvm_vcpu_has_pmu(vcpu) != valid_pmu)
- return -EINVAL;
-
- /* We can only differ with PerfMon, and anything else is an error */
- val ^= read_id_reg(vcpu, rd);
- val &= ~ARM64_FEATURE_MASK(ID_DFR0_EL1_PerfMon);
- if (val)
- return -EINVAL;
-
- if (valid_pmu)
- vcpu->kvm->arch.dfr0_pmuver.imp = perfmon_to_pmuver(perfmon);
- else
- vcpu->kvm->arch.dfr0_pmuver.unimp = perfmon_to_pmuver(perfmon);
-
- return 0;
-}
-
-/*
- * cpufeature ID register user accessors
- *
- * For now, these registers are immutable for userspace, so no values
- * are stored, and for set_id_reg() we don't allow the effective value
- * to be changed.
- */
-static int get_id_reg(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
- u64 *val)
-{
- *val = read_id_reg(vcpu, rd);
- return 0;
-}
-
-static int set_id_reg(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
- u64 val)
-{
- /* This is what we mean by invariant: you can't change it. */
- if (val != read_id_reg(vcpu, rd))
- return -EINVAL;
-
- return 0;
-}
-
static int get_raz_reg(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
u64 *val)
{
@@ -1648,50 +1358,6 @@ static unsigned int elx2_visibility(const struct kvm_vcpu *vcpu,
.visibility = elx2_visibility, \
}
-/* 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, \
-}
-
-/* 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, \
-}
-
-/*
- * sys_reg_desc initialiser for architecturally unallocated cpufeature ID
- * 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 \
-}
-
-/*
- * sys_reg_desc initialiser for known ID registers that we hide from guests.
- * 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, \
-}
-
static bool access_sp_el1(struct kvm_vcpu *vcpu,
struct sys_reg_params *p,
const struct sys_reg_desc *r)
@@ -1782,87 +1448,6 @@ static const struct sys_reg_desc sys_reg_descs[] = {
{ SYS_DESC(SYS_MPIDR_EL1), NULL, reset_mpidr, MPIDR_EL1 },
- /*
- * ID regs: all ID_SANITISED() entries here must have corresponding
- * entries in arm64_ftr_regs[].
- */
-
- /* AArch64 mappings of the AArch32 ID registers */
- /* 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, },
- ID_HIDDEN(ID_AFR0_EL1),
- AA32_ID_SANITISED(ID_MMFR0_EL1),
- AA32_ID_SANITISED(ID_MMFR1_EL1),
- AA32_ID_SANITISED(ID_MMFR2_EL1),
- AA32_ID_SANITISED(ID_MMFR3_EL1),
-
- /* CRm=2 */
- AA32_ID_SANITISED(ID_ISAR0_EL1),
- AA32_ID_SANITISED(ID_ISAR1_EL1),
- AA32_ID_SANITISED(ID_ISAR2_EL1),
- AA32_ID_SANITISED(ID_ISAR3_EL1),
- AA32_ID_SANITISED(ID_ISAR4_EL1),
- AA32_ID_SANITISED(ID_ISAR5_EL1),
- AA32_ID_SANITISED(ID_MMFR4_EL1),
- AA32_ID_SANITISED(ID_ISAR6_EL1),
-
- /* CRm=3 */
- AA32_ID_SANITISED(MVFR0_EL1),
- AA32_ID_SANITISED(MVFR1_EL1),
- AA32_ID_SANITISED(MVFR2_EL1),
- ID_UNALLOCATED(3,3),
- AA32_ID_SANITISED(ID_PFR2_EL1),
- ID_HIDDEN(ID_DFR1_EL1),
- AA32_ID_SANITISED(ID_MMFR5_EL1),
- ID_UNALLOCATED(3,7),
-
- /* 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, },
- ID_SANITISED(ID_AA64PFR1_EL1),
- ID_UNALLOCATED(4,2),
- ID_UNALLOCATED(4,3),
- ID_SANITISED(ID_AA64ZFR0_EL1),
- ID_HIDDEN(ID_AA64SMFR0_EL1),
- ID_UNALLOCATED(4,6),
- 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, },
- ID_SANITISED(ID_AA64DFR1_EL1),
- ID_UNALLOCATED(5,2),
- ID_UNALLOCATED(5,3),
- ID_HIDDEN(ID_AA64AFR0_EL1),
- ID_HIDDEN(ID_AA64AFR1_EL1),
- ID_UNALLOCATED(5,6),
- ID_UNALLOCATED(5,7),
-
- /* CRm=6 */
- ID_SANITISED(ID_AA64ISAR0_EL1),
- ID_SANITISED(ID_AA64ISAR1_EL1),
- ID_SANITISED(ID_AA64ISAR2_EL1),
- ID_UNALLOCATED(6,3),
- ID_UNALLOCATED(6,4),
- ID_UNALLOCATED(6,5),
- ID_UNALLOCATED(6,6),
- ID_UNALLOCATED(6,7),
-
- /* CRm=7 */
- ID_SANITISED(ID_AA64MMFR0_EL1),
- ID_SANITISED(ID_AA64MMFR1_EL1),
- ID_SANITISED(ID_AA64MMFR2_EL1),
- ID_UNALLOCATED(7,3),
- ID_UNALLOCATED(7,4),
- ID_UNALLOCATED(7,5),
- ID_UNALLOCATED(7,6),
- ID_UNALLOCATED(7,7),
-
{ SYS_DESC(SYS_SCTLR_EL1), access_vm_reg, reset_val, SCTLR_EL1, 0x00C50078 },
{ SYS_DESC(SYS_ACTLR_EL1), access_actlr, reset_actlr, ACTLR_EL1 },
{ SYS_DESC(SYS_CPACR_EL1), NULL, reset_val, CPACR_EL1, 0 },
@@ -2540,8 +2125,8 @@ static const struct sys_reg_desc cp15_64_regs[] = {
{ SYS_DESC(SYS_AARCH32_CNTP_CVAL), access_arch_timer },
};
-static bool check_sysreg_table(const struct sys_reg_desc *table, unsigned int n,
- bool is_32)
+bool check_sysreg_table(const struct sys_reg_desc *table, unsigned int n,
+ bool is_32)
{
unsigned int i;
@@ -2566,7 +2151,7 @@ int kvm_handle_cp14_load_store(struct kvm_vcpu *vcpu)
return 1;
}
-static void perform_access(struct kvm_vcpu *vcpu,
+void perform_access(struct kvm_vcpu *vcpu,
struct sys_reg_params *params,
const struct sys_reg_desc *r)
{
@@ -2941,6 +2526,9 @@ int kvm_handle_sys_reg(struct kvm_vcpu *vcpu)
params = esr_sys64_to_params(esr);
params.regval = vcpu_get_reg(vcpu, Rt);
+ if (is_id_reg(reg_to_encoding(¶ms)))
+ return emulate_id_reg(vcpu, ¶ms);
+
if (!emulate_sys_reg(vcpu, ¶ms))
return 1;
@@ -3160,6 +2748,7 @@ 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;
+ struct sys_reg_params params;
int err;
if ((reg->id & KVM_REG_ARM_COPROC_MASK) == KVM_REG_ARM_DEMUX)
@@ -3169,6 +2758,12 @@ int kvm_arm_sys_reg_get_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg
if (err != -ENOENT)
return err;
+ if (!index_to_params(reg->id, ¶ms))
+ return -ENOENT;
+
+ if (is_id_reg(reg_to_encoding(¶ms)))
+ return kvm_arm_get_id_reg(vcpu, reg);
+
return kvm_sys_reg_get_user(vcpu, reg,
sys_reg_descs, ARRAY_SIZE(sys_reg_descs));
}
@@ -3204,6 +2799,7 @@ 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;
+ struct sys_reg_params params;
int err;
if ((reg->id & KVM_REG_ARM_COPROC_MASK) == KVM_REG_ARM_DEMUX)
@@ -3213,6 +2809,12 @@ int kvm_arm_sys_reg_set_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg
if (err != -ENOENT)
return err;
+ if (!index_to_params(reg->id, ¶ms))
+ return -ENOENT;
+
+ if (is_id_reg(reg_to_encoding(¶ms)))
+ return kvm_arm_set_id_reg(vcpu, reg);
+
return kvm_sys_reg_set_user(vcpu, reg,
sys_reg_descs, ARRAY_SIZE(sys_reg_descs));
}
@@ -3259,10 +2861,10 @@ static bool copy_reg_to_user(const struct sys_reg_desc *reg, u64 __user **uind)
return true;
}
-static int walk_one_sys_reg(const struct kvm_vcpu *vcpu,
- const struct sys_reg_desc *rd,
- u64 __user **uind,
- unsigned int *total)
+int walk_one_sys_reg(const struct kvm_vcpu *vcpu,
+ const struct sys_reg_desc *rd,
+ u64 __user **uind,
+ unsigned int *total)
{
/*
* Ignore registers we trap but don't save,
@@ -3303,6 +2905,7 @@ unsigned long kvm_arm_num_sys_reg_descs(struct kvm_vcpu *vcpu)
{
return ARRAY_SIZE(invariant_sys_regs)
+ num_demux_regs()
+ + kvm_arm_walk_id_regs(vcpu, (u64 __user *)NULL)
+ walk_sys_regs(vcpu, (u64 __user *)NULL);
}
@@ -3318,6 +2921,11 @@ int kvm_arm_copy_sys_reg_indices(struct kvm_vcpu *vcpu, u64 __user *uindices)
uindices++;
}
+ err = kvm_arm_walk_id_regs(vcpu, uindices);
+ if (err < 0)
+ return err;
+ uindices += err;
+
err = walk_sys_regs(vcpu, uindices);
if (err < 0)
return err;
@@ -3332,6 +2940,7 @@ int __init kvm_sys_reg_table_init(void)
unsigned int i;
/* Make sure tables are unique and in order. */
+ valid &= kvm_arm_check_idreg_table();
valid &= check_sysreg_table(sys_reg_descs, ARRAY_SIZE(sys_reg_descs), false);
valid &= check_sysreg_table(cp14_regs, ARRAY_SIZE(cp14_regs), true);
valid &= check_sysreg_table(cp14_64_regs, ARRAY_SIZE(cp14_64_regs), true);
diff --git a/arch/arm64/kvm/sys_regs.h b/arch/arm64/kvm/sys_regs.h
index 6b11f2cc7146..2f7750153f8e 100644
--- a/arch/arm64/kvm/sys_regs.h
+++ b/arch/arm64/kvm/sys_regs.h
@@ -210,6 +210,19 @@ find_reg(const struct sys_reg_params *params, const struct sys_reg_desc table[],
return __inline_bsearch((void *)pval, table, num, sizeof(table[0]), match_sys_reg);
}
+/*
+ * Return true if the register's (Op0, Op1, CRn, CRm, Op2) is
+ * (3, 0, 0, crm, op2), where 1<=crm<8, 0<=op2<8.
+ */
+static inline bool is_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) < 8);
+}
+
+void perform_access(struct kvm_vcpu *vcpu, struct sys_reg_params *params,
+ const struct sys_reg_desc *r);
const struct sys_reg_desc *get_reg_by_id(u64 id,
const struct sys_reg_desc table[],
unsigned int num);
@@ -220,6 +233,20 @@ int kvm_sys_reg_get_user(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg,
const struct sys_reg_desc table[], unsigned int num);
int kvm_sys_reg_set_user(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg,
const struct sys_reg_desc table[], unsigned int num);
+bool write_to_read_only(struct kvm_vcpu *vcpu,
+ struct sys_reg_params *params, const struct sys_reg_desc *r);
+unsigned int raz_visibility(const struct kvm_vcpu *vcpu, const struct sys_reg_desc *r);
+bool check_sysreg_table(const struct sys_reg_desc *table, unsigned int n,
+ bool is_32);
+int walk_one_sys_reg(const struct kvm_vcpu *vcpu,
+ const struct sys_reg_desc *rd,
+ u64 __user **uind,
+ unsigned int *total);
+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);
+int kvm_arm_set_id_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg);
+bool kvm_arm_check_idreg_table(void);
+int kvm_arm_walk_id_regs(struct kvm_vcpu *vcpu, u64 __user *uind);
#define AA32(_x) .aarch32_map = AA32_##_x
#define Op0(_x) .Op0 = _x
--
2.40.0.348.gf938b09366-goog
^ permalink raw reply related [flat|nested] 13+ messages in thread
* [PATCH v5 2/6] KVM: arm64: Save ID registers' sanitized value per guest
2023-04-02 18:37 [PATCH v5 0/6] Support writable CPU ID registers from userspace Jing Zhang
2023-04-02 18:37 ` [PATCH v5 1/6] KVM: arm64: Move CPU ID feature registers emulation into a separate file Jing Zhang
@ 2023-04-02 18:37 ` Jing Zhang
2023-04-02 18:37 ` [PATCH v5 3/6] KVM: arm64: Use per guest ID register for ID_AA64PFR0_EL1.[CSV2|CSV3] Jing Zhang
` (4 subsequent siblings)
6 siblings, 0 replies; 13+ messages in thread
From: Jing Zhang @ 2023-04-02 18:37 UTC (permalink / raw)
To: KVM, KVMARM, ARMLinux, Marc Zyngier, Oliver Upton
Cc: Will Deacon, Paolo Bonzini, James Morse, Alexandru Elisei,
Suzuki K Poulose, Fuad Tabba, Reiji Watanabe,
Raghavendra Rao Ananta, Jing Zhang
Introduce id_regs[] in kvm_arch as a storage of guest's ID registers,
and save ID registers' sanitized value in the array at KVM_CREATE_VM.
Use the saved ones when ID registers are read by the guest or
userspace (via KVM_GET_ONE_REG).
No functional change intended.
Co-developed-by: Reiji Watanabe <reijiw@google.com>
Signed-off-by: Reiji Watanabe <reijiw@google.com>
Signed-off-by: Jing Zhang <jingzhangos@google.com>
---
arch/arm64/include/asm/kvm_host.h | 21 +++++++++++++
arch/arm64/kvm/arm.c | 1 +
arch/arm64/kvm/id_regs.c | 49 +++++++++++++++++++++++++------
arch/arm64/kvm/sys_regs.c | 2 +-
arch/arm64/kvm/sys_regs.h | 1 +
5 files changed, 64 insertions(+), 10 deletions(-)
diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index a8e2c52b44aa..3b8a2cc0c7cd 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -177,6 +177,22 @@ struct kvm_smccc_features {
unsigned long vendor_hyp_bmap;
};
+/*
+ * Emualted CPU ID registers per VM
+ * (Op0, Op1, CRn, CRm, Op2) of the ID registers to be saved in it
+ * is (3, 0, 0, crm, op2), where 1<=crm<8, 0<=op2<8.
+ *
+ * These emulated idregs are VM-wide, but accessed from the context of a vCPU.
+ * Updating multiple id regs with dependencies needs to be guarded by
+ * kvm_arch.config_lock.
+ */
+#define KVM_ARM_ID_REG_NUM 56
+#define IDREG_IDX(id) (((sys_reg_CRm(id) - 1) << 3) | sys_reg_Op2(id))
+#define IDREG(kvm, id) kvm->arch.idregs.regs[IDREG_IDX(id)]
+struct kvm_idregs {
+ u64 regs[KVM_ARM_ID_REG_NUM];
+};
+
typedef unsigned int pkvm_handle_t;
struct kvm_protected_vm {
@@ -250,6 +266,9 @@ struct kvm_arch {
/* Hypercall features firmware registers' descriptor */
struct kvm_smccc_features smccc_feat;
+ /* Emulated CPU ID registers */
+ struct kvm_idregs idregs;
+
/*
* For an untrusted host VM, 'pkvm.handle' is used to lookup
* the associated pKVM instance in the hypervisor.
@@ -1025,6 +1044,8 @@ long kvm_vm_ioctl_mte_copy_tags(struct kvm *kvm,
int kvm_vm_ioctl_set_counter_offset(struct kvm *kvm,
struct kvm_arm_counter_offset *offset);
+void kvm_arm_init_id_regs(struct kvm *kvm);
+
/* Guest/host FPSIMD coordination helpers */
int kvm_arch_vcpu_run_map_fp(struct kvm_vcpu *vcpu);
void kvm_arch_vcpu_load_fp(struct kvm_vcpu *vcpu);
diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index 0e5a3ff8cc5a..571e24124a95 100644
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -165,6 +165,7 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type)
set_default_spectre(kvm);
kvm_arm_init_hypercalls(kvm);
+ kvm_arm_init_id_regs(kvm);
/*
* Initialise the default PMUver before there is a chance to
diff --git a/arch/arm64/kvm/id_regs.c b/arch/arm64/kvm/id_regs.c
index 638c0f8e4cd2..77f945c78d47 100644
--- a/arch/arm64/kvm/id_regs.c
+++ b/arch/arm64/kvm/id_regs.c
@@ -52,16 +52,9 @@ static u8 pmuver_to_perfmon(u8 pmuver)
}
}
-/* Read a sanitised cpufeature ID register by sys_reg_desc */
-static u64 read_id_reg(const struct kvm_vcpu *vcpu, struct sys_reg_desc const *r)
+u64 kvm_arm_read_id_reg(const struct kvm_vcpu *vcpu, u32 id)
{
- u32 id = reg_to_encoding(r);
- u64 val;
-
- if (sysreg_visible_as_raz(vcpu, r))
- return 0;
-
- val = read_sanitised_ftr_reg(id);
+ u64 val = IDREG(vcpu->kvm, id);
switch (id) {
case SYS_ID_AA64PFR0_EL1:
@@ -126,6 +119,14 @@ static u64 read_id_reg(const struct kvm_vcpu *vcpu, struct sys_reg_desc const *r
return val;
}
+static u64 read_id_reg(const struct kvm_vcpu *vcpu, struct sys_reg_desc const *r)
+{
+ if (sysreg_visible_as_raz(vcpu, r))
+ return 0;
+
+ return kvm_arm_read_id_reg(vcpu, reg_to_encoding(r));
+}
+
/* cpufeature ID register access trap handlers */
static bool access_id_reg(struct kvm_vcpu *vcpu,
@@ -494,3 +495,33 @@ int kvm_arm_walk_id_regs(struct kvm_vcpu *vcpu, u64 __user *uind)
}
return total;
}
+
+/*
+ * Set the guest's ID registers that are defined in id_reg_descs[]
+ * with ID_SANITISED() to the host's sanitized value.
+ */
+void kvm_arm_init_id_regs(struct kvm *kvm)
+{
+ int i;
+ u32 id;
+ 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);
+ IDREG(kvm, id) = val;
+ }
+}
diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index 40be494391fd..3af9f85aa976 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -364,7 +364,7 @@ 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 = kvm_arm_read_id_reg(vcpu, SYS_ID_AA64MMFR1_EL1);
u32 sr = reg_to_encoding(r);
if (!(val & (0xfUL << ID_AA64MMFR1_EL1_LO_SHIFT))) {
diff --git a/arch/arm64/kvm/sys_regs.h b/arch/arm64/kvm/sys_regs.h
index 2f7750153f8e..326ca28c1117 100644
--- a/arch/arm64/kvm/sys_regs.h
+++ b/arch/arm64/kvm/sys_regs.h
@@ -247,6 +247,7 @@ int kvm_arm_get_id_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg);
int kvm_arm_set_id_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg);
bool kvm_arm_check_idreg_table(void);
int kvm_arm_walk_id_regs(struct kvm_vcpu *vcpu, u64 __user *uind);
+u64 kvm_arm_read_id_reg(const struct kvm_vcpu *vcpu, u32 id);
#define AA32(_x) .aarch32_map = AA32_##_x
#define Op0(_x) .Op0 = _x
--
2.40.0.348.gf938b09366-goog
^ permalink raw reply related [flat|nested] 13+ messages in thread
* [PATCH v5 3/6] KVM: arm64: Use per guest ID register for ID_AA64PFR0_EL1.[CSV2|CSV3]
2023-04-02 18:37 [PATCH v5 0/6] Support writable CPU ID registers from userspace Jing Zhang
2023-04-02 18:37 ` [PATCH v5 1/6] KVM: arm64: Move CPU ID feature registers emulation into a separate file Jing Zhang
2023-04-02 18:37 ` [PATCH v5 2/6] KVM: arm64: Save ID registers' sanitized value per guest Jing Zhang
@ 2023-04-02 18:37 ` Jing Zhang
2023-04-02 18:37 ` [PATCH v5 4/6] KVM: arm64: Use per guest ID register for ID_AA64DFR0_EL1.PMUVer Jing Zhang
` (3 subsequent siblings)
6 siblings, 0 replies; 13+ messages in thread
From: Jing Zhang @ 2023-04-02 18:37 UTC (permalink / raw)
To: KVM, KVMARM, ARMLinux, Marc Zyngier, Oliver Upton
Cc: Will Deacon, Paolo Bonzini, James Morse, Alexandru Elisei,
Suzuki K Poulose, Fuad Tabba, Reiji Watanabe,
Raghavendra Rao Ananta, Jing Zhang
With per guest ID registers, ID_AA64PFR0_EL1.[CSV2|CSV3] settings from
userspace can be stored in its corresponding ID register.
The setting of CSV bits for protected VMs are removed according to the
discussion from Fuad below:
https://lore.kernel.org/all/CA+EHjTwXA9TprX4jeG+-D+c8v9XG+oFdU1o6TSkvVye145_OvA@mail.gmail.com
Besides the removal of CSV bits setting for protected VMs, No other
functional change intended.
Signed-off-by: Jing Zhang <jingzhangos@google.com>
---
arch/arm64/include/asm/kvm_host.h | 2 --
arch/arm64/kvm/arm.c | 17 ----------------
arch/arm64/kvm/hyp/nvhe/sys_regs.c | 7 -------
arch/arm64/kvm/id_regs.c | 31 ++++++++++++++++++++++--------
4 files changed, 23 insertions(+), 34 deletions(-)
diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index 3b8a2cc0c7cd..283e1f30cec5 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -256,8 +256,6 @@ struct kvm_arch {
cpumask_var_t supported_cpus;
- u8 pfr0_csv2;
- u8 pfr0_csv3;
struct {
u8 imp:4;
u8 unimp:4;
diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index 571e24124a95..483c7377e092 100644
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -104,22 +104,6 @@ static int kvm_arm_default_max_vcpus(void)
return vgic_present ? kvm_vgic_get_max_vcpus() : KVM_MAX_VCPUS;
}
-static void set_default_spectre(struct kvm *kvm)
-{
- /*
- * The default is to expose CSV2 == 1 if the HW isn't affected.
- * Although this is a per-CPU feature, we make it global because
- * asymmetric systems are just a nuisance.
- *
- * Userspace can override this as long as it doesn't promise
- * the impossible.
- */
- if (arm64_get_spectre_v2_state() == SPECTRE_UNAFFECTED)
- kvm->arch.pfr0_csv2 = 1;
- if (arm64_get_meltdown_state() == SPECTRE_UNAFFECTED)
- kvm->arch.pfr0_csv3 = 1;
-}
-
/**
* kvm_arch_init_vm - initializes a VM data structure
* @kvm: pointer to the KVM struct
@@ -163,7 +147,6 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type)
/* The maximum number of VCPUs is limited by the host's GIC model */
kvm->max_vcpus = kvm_arm_default_max_vcpus();
- set_default_spectre(kvm);
kvm_arm_init_hypercalls(kvm);
kvm_arm_init_id_regs(kvm);
diff --git a/arch/arm64/kvm/hyp/nvhe/sys_regs.c b/arch/arm64/kvm/hyp/nvhe/sys_regs.c
index 08d2b004f4b7..edd969a1f36b 100644
--- a/arch/arm64/kvm/hyp/nvhe/sys_regs.c
+++ b/arch/arm64/kvm/hyp/nvhe/sys_regs.c
@@ -85,19 +85,12 @@ static u64 get_restricted_features_unsigned(u64 sys_reg_val,
static u64 get_pvm_id_aa64pfr0(const struct kvm_vcpu *vcpu)
{
- const struct kvm *kvm = (const struct kvm *)kern_hyp_va(vcpu->kvm);
u64 set_mask = 0;
u64 allow_mask = PVM_ID_AA64PFR0_ALLOW;
set_mask |= get_restricted_features_unsigned(id_aa64pfr0_el1_sys_val,
PVM_ID_AA64PFR0_RESTRICT_UNSIGNED);
- /* Spectre and Meltdown mitigation in KVM */
- set_mask |= FIELD_PREP(ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_CSV2),
- (u64)kvm->arch.pfr0_csv2);
- set_mask |= FIELD_PREP(ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_CSV3),
- (u64)kvm->arch.pfr0_csv3);
-
return (id_aa64pfr0_el1_sys_val & allow_mask) | set_mask;
}
diff --git a/arch/arm64/kvm/id_regs.c b/arch/arm64/kvm/id_regs.c
index 77f945c78d47..c6525efe8058 100644
--- a/arch/arm64/kvm/id_regs.c
+++ b/arch/arm64/kvm/id_regs.c
@@ -61,12 +61,6 @@ u64 kvm_arm_read_id_reg(const struct kvm_vcpu *vcpu, u32 id)
if (!vcpu_has_sve(vcpu))
val &= ~ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_SVE);
val &= ~ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_AMU);
- val &= ~ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_CSV2);
- val |= FIELD_PREP(ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_CSV2),
- (u64)vcpu->kvm->arch.pfr0_csv2);
- val &= ~ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_CSV3);
- val |= FIELD_PREP(ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_CSV3),
- (u64)vcpu->kvm->arch.pfr0_csv3);
if (kvm_vgic_global_state.type == VGIC_V3) {
val &= ~ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_GIC);
val |= FIELD_PREP(ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_GIC), 1);
@@ -201,6 +195,7 @@ static int set_id_aa64pfr0_el1(struct kvm_vcpu *vcpu,
u64 val)
{
u8 csv2, csv3;
+ u64 sval = val;
/*
* Allow AA64PFR0_EL1.CSV2 to be set from userspace as long as
@@ -225,8 +220,7 @@ static int set_id_aa64pfr0_el1(struct kvm_vcpu *vcpu,
if (val)
return -EINVAL;
- vcpu->kvm->arch.pfr0_csv2 = csv2;
- vcpu->kvm->arch.pfr0_csv3 = csv3;
+ IDREG(vcpu->kvm, reg_to_encoding(rd)) = sval;
return 0;
}
@@ -524,4 +518,25 @@ void kvm_arm_init_id_regs(struct kvm *kvm)
val = read_sanitised_ftr_reg(id);
IDREG(kvm, id) = val;
}
+
+ /*
+ * The default is to expose CSV2 == 1 if the HW isn't affected.
+ * Although this is a per-CPU feature, we make it global because
+ * asymmetric systems are just a nuisance.
+ *
+ * Userspace can override this as long as it doesn't promise
+ * the impossible.
+ */
+ val = IDREG(kvm, SYS_ID_AA64PFR0_EL1);
+
+ if (arm64_get_spectre_v2_state() == SPECTRE_UNAFFECTED) {
+ val &= ~ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_CSV2);
+ val |= FIELD_PREP(ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_CSV2), 1);
+ }
+ if (arm64_get_meltdown_state() == SPECTRE_UNAFFECTED) {
+ val &= ~ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_CSV3);
+ val |= FIELD_PREP(ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_CSV3), 1);
+ }
+
+ IDREG(kvm, SYS_ID_AA64PFR0_EL1) = val;
}
--
2.40.0.348.gf938b09366-goog
^ permalink raw reply related [flat|nested] 13+ messages in thread
* [PATCH v5 4/6] KVM: arm64: Use per guest ID register for ID_AA64DFR0_EL1.PMUVer
2023-04-02 18:37 [PATCH v5 0/6] Support writable CPU ID registers from userspace Jing Zhang
` (2 preceding siblings ...)
2023-04-02 18:37 ` [PATCH v5 3/6] KVM: arm64: Use per guest ID register for ID_AA64PFR0_EL1.[CSV2|CSV3] Jing Zhang
@ 2023-04-02 18:37 ` Jing Zhang
2023-04-02 18:37 ` [PATCH v5 5/6] KVM: arm64: Introduce ID register specific descriptor Jing Zhang
` (2 subsequent siblings)
6 siblings, 0 replies; 13+ messages in thread
From: Jing Zhang @ 2023-04-02 18:37 UTC (permalink / raw)
To: KVM, KVMARM, ARMLinux, Marc Zyngier, Oliver Upton
Cc: Will Deacon, Paolo Bonzini, James Morse, Alexandru Elisei,
Suzuki K Poulose, Fuad Tabba, Reiji Watanabe,
Raghavendra Rao Ananta, Jing Zhang
With per guest ID registers, PMUver settings from userspace
can be stored in its corresponding ID register.
No functional change intended.
Signed-off-by: Jing Zhang <jingzhangos@google.com>
---
arch/arm64/include/asm/kvm_host.h | 11 ++++---
arch/arm64/kvm/arm.c | 6 ----
arch/arm64/kvm/id_regs.c | 51 +++++++++++++++++++++++++------
include/kvm/arm_pmu.h | 5 +--
4 files changed, 50 insertions(+), 23 deletions(-)
diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index 283e1f30cec5..28448e53bbf3 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -244,6 +244,12 @@ struct kvm_arch {
#define KVM_ARCH_FLAG_VM_COUNTER_OFFSET 6
/* Timer PPIs made immutable */
#define KVM_ARCH_FLAG_TIMER_PPIS_IMMUTABLE 7
+ /*
+ * AA64DFR0_EL1.PMUver was set as ID_AA64DFR0_EL1_PMUVer_IMP_DEF
+ * or DFR0_EL1.PerfMon was set as ID_DFR0_EL1_PerfMon_IMPDEF from
+ * userspace for VCPUs without PMU.
+ */
+#define KVM_ARCH_FLAG_VCPU_HAS_IMP_DEF_PMU 8
unsigned long flags;
@@ -256,11 +262,6 @@ struct kvm_arch {
cpumask_var_t supported_cpus;
- struct {
- u8 imp:4;
- u8 unimp:4;
- } dfr0_pmuver;
-
/* Hypercall features firmware registers' descriptor */
struct kvm_smccc_features smccc_feat;
diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index 483c7377e092..48d738148e84 100644
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -150,12 +150,6 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type)
kvm_arm_init_hypercalls(kvm);
kvm_arm_init_id_regs(kvm);
- /*
- * Initialise the default PMUver before there is a chance to
- * create an actual PMU.
- */
- kvm->arch.dfr0_pmuver.imp = kvm_arm_pmu_get_pmuver_limit();
-
return 0;
err_free_cpumask:
diff --git a/arch/arm64/kvm/id_regs.c b/arch/arm64/kvm/id_regs.c
index c6525efe8058..e92eacb0ad32 100644
--- a/arch/arm64/kvm/id_regs.c
+++ b/arch/arm64/kvm/id_regs.c
@@ -21,9 +21,12 @@
static u8 vcpu_pmuver(const struct kvm_vcpu *vcpu)
{
if (kvm_vcpu_has_pmu(vcpu))
- return vcpu->kvm->arch.dfr0_pmuver.imp;
+ return FIELD_GET(ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_PMUVer),
+ IDREG(vcpu->kvm, SYS_ID_AA64DFR0_EL1));
+ else if (test_bit(KVM_ARCH_FLAG_VCPU_HAS_IMP_DEF_PMU, &vcpu->kvm->arch.flags))
+ return ID_AA64DFR0_EL1_PMUVer_IMP_DEF;
- return vcpu->kvm->arch.dfr0_pmuver.unimp;
+ return 0;
}
static u8 perfmon_to_pmuver(u8 perfmon)
@@ -256,10 +259,20 @@ static int set_id_aa64dfr0_el1(struct kvm_vcpu *vcpu,
if (val)
return -EINVAL;
- if (valid_pmu)
- vcpu->kvm->arch.dfr0_pmuver.imp = pmuver;
- else
- vcpu->kvm->arch.dfr0_pmuver.unimp = pmuver;
+ if (valid_pmu) {
+ mutex_lock(&vcpu->kvm->arch.config_lock);
+ IDREG(vcpu->kvm, SYS_ID_AA64DFR0_EL1) &= ~ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_PMUVer);
+ IDREG(vcpu->kvm, SYS_ID_AA64DFR0_EL1) |=
+ FIELD_PREP(ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_PMUVer), pmuver);
+
+ IDREG(vcpu->kvm, SYS_ID_DFR0_EL1) &= ~ARM64_FEATURE_MASK(ID_DFR0_EL1_PerfMon);
+ IDREG(vcpu->kvm, SYS_ID_DFR0_EL1) |=
+ FIELD_PREP(ARM64_FEATURE_MASK(ID_DFR0_EL1_PerfMon), pmuver_to_perfmon(pmuver));
+ mutex_unlock(&vcpu->kvm->arch.config_lock);
+ } else {
+ assign_bit(KVM_ARCH_FLAG_VCPU_HAS_IMP_DEF_PMU, &vcpu->kvm->arch.flags,
+ pmuver == ID_AA64DFR0_EL1_PMUVer_IMP_DEF);
+ }
return 0;
}
@@ -296,10 +309,20 @@ static int set_id_dfr0_el1(struct kvm_vcpu *vcpu,
if (val)
return -EINVAL;
- if (valid_pmu)
- vcpu->kvm->arch.dfr0_pmuver.imp = perfmon_to_pmuver(perfmon);
- else
- vcpu->kvm->arch.dfr0_pmuver.unimp = perfmon_to_pmuver(perfmon);
+ if (valid_pmu) {
+ mutex_lock(&vcpu->kvm->arch.config_lock);
+ IDREG(vcpu->kvm, SYS_ID_DFR0_EL1) &= ~ARM64_FEATURE_MASK(ID_DFR0_EL1_PerfMon);
+ IDREG(vcpu->kvm, SYS_ID_DFR0_EL1) |=
+ FIELD_PREP(ARM64_FEATURE_MASK(ID_DFR0_EL1_PerfMon), perfmon);
+
+ IDREG(vcpu->kvm, SYS_ID_AA64DFR0_EL1) &= ~ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_PMUVer);
+ IDREG(vcpu->kvm, SYS_ID_AA64DFR0_EL1) |=
+ FIELD_PREP(ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_PMUVer), perfmon_to_pmuver(perfmon));
+ mutex_unlock(&vcpu->kvm->arch.config_lock);
+ } else {
+ assign_bit(KVM_ARCH_FLAG_VCPU_HAS_IMP_DEF_PMU, &vcpu->kvm->arch.flags,
+ perfmon == ID_DFR0_EL1_PerfMon_IMPDEF);
+ }
return 0;
}
@@ -539,4 +562,12 @@ void kvm_arm_init_id_regs(struct kvm *kvm)
}
IDREG(kvm, SYS_ID_AA64PFR0_EL1) = val;
+
+ /*
+ * Initialise the default PMUver before there is a chance to
+ * create an actual PMU.
+ */
+ IDREG(kvm, SYS_ID_AA64DFR0_EL1) &= ~ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_PMUVer);
+ IDREG(kvm, SYS_ID_AA64DFR0_EL1) |=
+ FIELD_PREP(ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_PMUVer), kvm_arm_pmu_get_pmuver_limit());
}
diff --git a/include/kvm/arm_pmu.h b/include/kvm/arm_pmu.h
index 628775334d5e..856ac59b6821 100644
--- a/include/kvm/arm_pmu.h
+++ b/include/kvm/arm_pmu.h
@@ -92,8 +92,9 @@ void kvm_vcpu_pmu_restore_host(struct kvm_vcpu *vcpu);
/*
* Evaluates as true when emulating PMUv3p5, and false otherwise.
*/
-#define kvm_pmu_is_3p5(vcpu) \
- (vcpu->kvm->arch.dfr0_pmuver.imp >= ID_AA64DFR0_EL1_PMUVer_V3P5)
+#define kvm_pmu_is_3p5(vcpu) \
+ (FIELD_GET(ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_PMUVer), \
+ IDREG(vcpu->kvm, SYS_ID_AA64DFR0_EL1)) >= ID_AA64DFR0_EL1_PMUVer_V3P5)
u8 kvm_arm_pmu_get_pmuver_limit(void);
--
2.40.0.348.gf938b09366-goog
^ permalink raw reply related [flat|nested] 13+ messages in thread
* [PATCH v5 5/6] KVM: arm64: Introduce ID register specific descriptor
2023-04-02 18:37 [PATCH v5 0/6] Support writable CPU ID registers from userspace Jing Zhang
` (3 preceding siblings ...)
2023-04-02 18:37 ` [PATCH v5 4/6] KVM: arm64: Use per guest ID register for ID_AA64DFR0_EL1.PMUVer Jing Zhang
@ 2023-04-02 18:37 ` Jing Zhang
2023-04-03 12:27 ` Marc Zyngier
2023-04-02 18:37 ` [PATCH v5 6/6] KVM: arm64: Refactor writings for PMUVer/CSV2/CSV3 Jing Zhang
2023-04-03 10:30 ` [PATCH v5 0/6] Support writable CPU ID registers from userspace Marc Zyngier
6 siblings, 1 reply; 13+ messages in thread
From: Jing Zhang @ 2023-04-02 18:37 UTC (permalink / raw)
To: KVM, KVMARM, ARMLinux, Marc Zyngier, Oliver Upton
Cc: Will Deacon, Paolo Bonzini, James Morse, Alexandru Elisei,
Suzuki K Poulose, Fuad Tabba, Reiji Watanabe,
Raghavendra Rao Ananta, Jing Zhang
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@google.com>
Signed-off-by: Reiji Watanabe <reijiw@google.com>
Signed-off-by: Jing Zhang <jingzhangos@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
^ permalink raw reply related [flat|nested] 13+ messages in thread
* [PATCH v5 6/6] KVM: arm64: Refactor writings for PMUVer/CSV2/CSV3
2023-04-02 18:37 [PATCH v5 0/6] Support writable CPU ID registers from userspace Jing Zhang
` (4 preceding siblings ...)
2023-04-02 18:37 ` [PATCH v5 5/6] KVM: arm64: Introduce ID register specific descriptor Jing Zhang
@ 2023-04-02 18:37 ` Jing Zhang
2023-04-03 14:55 ` Marc Zyngier
2023-04-03 10:30 ` [PATCH v5 0/6] Support writable CPU ID registers from userspace Marc Zyngier
6 siblings, 1 reply; 13+ messages in thread
From: Jing Zhang @ 2023-04-02 18:37 UTC (permalink / raw)
To: KVM, KVMARM, ARMLinux, Marc Zyngier, Oliver Upton
Cc: Will Deacon, Paolo Bonzini, James Morse, Alexandru Elisei,
Suzuki K Poulose, Fuad Tabba, Reiji Watanabe,
Raghavendra Rao Ananta, Jing Zhang
Refactor writings for ID_AA64PFR0_EL1.[CSV2|CSV3],
ID_AA64DFR0_EL1.PMUVer and ID_DFR0_ELF.PerfMon based on utilities
introduced by ID register descriptor.
No functional change intended.
Co-developed-by: Reiji Watanabe <reijiw@google.com>
Signed-off-by: Reiji Watanabe <reijiw@google.com>
Signed-off-by: Jing Zhang <jingzhangos@google.com>
---
arch/arm64/include/asm/cpufeature.h | 5 +
arch/arm64/kernel/cpufeature.c | 8 +-
arch/arm64/kvm/id_regs.c | 262 +++++++++++++++++++---------
arch/arm64/kvm/sys_regs.c | 3 +-
arch/arm64/kvm/sys_regs.h | 2 +-
5 files changed, 191 insertions(+), 89 deletions(-)
diff --git a/arch/arm64/include/asm/cpufeature.h b/arch/arm64/include/asm/cpufeature.h
index 6bf013fb110d..f17e74afe3e9 100644
--- a/arch/arm64/include/asm/cpufeature.h
+++ b/arch/arm64/include/asm/cpufeature.h
@@ -915,6 +915,7 @@ static inline unsigned int get_vmid_bits(u64 mmfr1)
return 8;
}
+s64 arm64_ftr_safe_value(const struct arm64_ftr_bits *ftrp, s64 new, s64 cur);
struct arm64_ftr_reg *get_arm64_ftr_reg(u32 sys_id);
extern struct arm64_ftr_override id_aa64mmfr1_override;
@@ -925,6 +926,10 @@ extern struct arm64_ftr_override id_aa64smfr0_override;
extern struct arm64_ftr_override id_aa64isar1_override;
extern struct arm64_ftr_override id_aa64isar2_override;
+extern const struct arm64_ftr_bits ftr_id_dfr0[];
+extern const struct arm64_ftr_bits ftr_id_aa64pfr0[];
+extern const struct arm64_ftr_bits ftr_id_aa64dfr0[];
+
u32 get_kvm_ipa_limit(void);
void dump_cpu_features(void);
diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index c331c49a7d19..5b0e3379e5f8 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -225,7 +225,7 @@ static const struct arm64_ftr_bits ftr_id_aa64isar2[] = {
ARM64_FTR_END,
};
-static const struct arm64_ftr_bits ftr_id_aa64pfr0[] = {
+const struct arm64_ftr_bits ftr_id_aa64pfr0[] = {
ARM64_FTR_BITS(FTR_HIDDEN, FTR_NONSTRICT, FTR_LOWER_SAFE, ID_AA64PFR0_EL1_CSV3_SHIFT, 4, 0),
ARM64_FTR_BITS(FTR_HIDDEN, FTR_NONSTRICT, FTR_LOWER_SAFE, ID_AA64PFR0_EL1_CSV2_SHIFT, 4, 0),
ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64PFR0_EL1_DIT_SHIFT, 4, 0),
@@ -426,7 +426,7 @@ static const struct arm64_ftr_bits ftr_id_mmfr0[] = {
ARM64_FTR_END,
};
-static const struct arm64_ftr_bits ftr_id_aa64dfr0[] = {
+const struct arm64_ftr_bits ftr_id_aa64dfr0[] = {
S_ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64DFR0_EL1_DoubleLock_SHIFT, 4, 0),
ARM64_FTR_BITS(FTR_HIDDEN, FTR_NONSTRICT, FTR_LOWER_SAFE, ID_AA64DFR0_EL1_PMSVer_SHIFT, 4, 0),
ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64DFR0_EL1_CTX_CMPs_SHIFT, 4, 0),
@@ -578,7 +578,7 @@ static const struct arm64_ftr_bits ftr_id_pfr2[] = {
ARM64_FTR_END,
};
-static const struct arm64_ftr_bits ftr_id_dfr0[] = {
+const struct arm64_ftr_bits ftr_id_dfr0[] = {
/* [31:28] TraceFilt */
S_ARM64_FTR_BITS(FTR_HIDDEN, FTR_NONSTRICT, FTR_EXACT, ID_DFR0_EL1_PerfMon_SHIFT, 4, 0),
ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_DFR0_EL1_MProfDbg_SHIFT, 4, 0),
@@ -791,7 +791,7 @@ static u64 arm64_ftr_set_value(const struct arm64_ftr_bits *ftrp, s64 reg,
return reg;
}
-static s64 arm64_ftr_safe_value(const struct arm64_ftr_bits *ftrp, s64 new,
+s64 arm64_ftr_safe_value(const struct arm64_ftr_bits *ftrp, s64 new,
s64 cur)
{
s64 ret = 0;
diff --git a/arch/arm64/kvm/id_regs.c b/arch/arm64/kvm/id_regs.c
index af86001e2686..395eaf84a0ab 100644
--- a/arch/arm64/kvm/id_regs.c
+++ b/arch/arm64/kvm/id_regs.c
@@ -39,6 +39,64 @@ struct id_reg_desc {
u64 (*read_kvm_sanitised_reg)(const struct id_reg_desc *idr);
};
+static struct id_reg_desc id_reg_descs[];
+
+/**
+ * arm64_check_features() - Check if a feature register value constitutes
+ * a subset of features indicated by @limit.
+ *
+ * @ftrp: Pointer to an array of arm64_ftr_bits. It must be terminated by
+ * an item whose width field is zero.
+ * @writable_mask: Indicates writable feature bits.
+ * @val: The feature register value to check
+ * @limit: The limit value of the feature register
+ *
+ * This function will check if each feature field of @val is the "safe" value
+ * against @limit based on @ftrp[], each of which specifies the target field
+ * (shift, width), whether or not the field is for a signed value (sign),
+ * how the field is determined to be "safe" (type), and the safe value
+ * (safe_val) when type == FTR_EXACT (safe_val won't be used by this
+ * function when type != FTR_EXACT). Any other fields in arm64_ftr_bits
+ * won't be used by this function. If a field value in @val is the same
+ * as the one in @limit, it is always considered the safe value regardless
+ * of the type. For register fields that are not in writable, only the value
+ * in @limit is considered the safe value.
+ *
+ * Return: 0 if all the fields are safe. Otherwise, return negative errno.
+ */
+static int arm64_check_features(const struct arm64_ftr_bits *ftrp,
+ u64 writable_mask, u64 val, u64 limit)
+{
+ u64 mask = 0;
+
+ for (; ftrp && ftrp->width; ftrp++) {
+ s64 f_val, f_lim, safe_val;
+ u64 ftr_mask;
+
+ ftr_mask = arm64_ftr_mask(ftrp);
+ if ((ftr_mask & writable_mask) != ftr_mask)
+ continue;
+
+ f_val = arm64_ftr_value(ftrp, val);
+ f_lim = arm64_ftr_value(ftrp, limit);
+ mask |= ftr_mask;
+
+ if (f_val == f_lim)
+ safe_val = f_val;
+ else
+ safe_val = arm64_ftr_safe_value(ftrp, f_val, f_lim);
+
+ if (safe_val != f_val)
+ return -E2BIG;
+ }
+
+ /* For fields that are not writable, values in limit are the safe values. */
+ if ((val & ~mask) != (limit & ~mask))
+ return -E2BIG;
+
+ return 0;
+}
+
static u8 vcpu_pmuver(const struct kvm_vcpu *vcpu)
{
if (kvm_vcpu_has_pmu(vcpu))
@@ -84,7 +142,6 @@ u64 kvm_arm_read_id_reg(const struct kvm_vcpu *vcpu, u32 id)
case SYS_ID_AA64PFR0_EL1:
if (!vcpu_has_sve(vcpu))
val &= ~ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_SVE);
- val &= ~ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_AMU);
if (kvm_vgic_global_state.type == VGIC_V3) {
val &= ~ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_GIC);
val |= FIELD_PREP(ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_GIC), 1);
@@ -111,15 +168,10 @@ u64 kvm_arm_read_id_reg(const struct kvm_vcpu *vcpu, u32 id)
val &= ~ARM64_FEATURE_MASK(ID_AA64ISAR2_EL1_WFxT);
break;
case SYS_ID_AA64DFR0_EL1:
- /* Limit debug to ARMv8.0 */
- val &= ~ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_DebugVer);
- val |= FIELD_PREP(ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_DebugVer), 6);
/* Set PMUver to the required version */
val &= ~ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_PMUVer);
val |= FIELD_PREP(ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_PMUVer),
vcpu_pmuver(vcpu));
- /* Hide SPE from guests */
- val &= ~ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_PMSVer);
break;
case SYS_ID_DFR0_EL1:
val &= ~ARM64_FEATURE_MASK(ID_DFR0_EL1_PerfMon);
@@ -178,9 +230,16 @@ static int get_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,
u64 val)
{
- /* This is what we mean by invariant: you can't change it. */
- if (val != read_id_reg(vcpu, rd))
- return -EINVAL;
+ int ret;
+ int id = reg_to_encoding(rd);
+ const struct id_reg_desc *idr = &id_reg_descs[IDREG_IDX(id)];
+
+ ret = arm64_check_features(idr->ftr_bits, idr->writable_mask, val,
+ idr->read_kvm_sanitised_reg ? idr->read_kvm_sanitised_reg(idr) : 0);
+ if (ret)
+ return ret;
+
+ IDREG(vcpu->kvm, id) = val;
return 0;
}
@@ -219,12 +278,39 @@ 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 u64 read_sanitised_id_aa64pfr0_el1(const struct id_reg_desc *idr)
+{
+ u64 val;
+ u32 id = reg_to_encoding(&idr->reg_desc);
+
+ val = read_sanitised_ftr_reg(id);
+ /*
+ * The default is to expose CSV2 == 1 if the HW isn't affected.
+ * Although this is a per-CPU feature, we make it global because
+ * asymmetric systems are just a nuisance.
+ *
+ * Userspace can override this as long as it doesn't promise
+ * the impossible.
+ */
+ if (arm64_get_spectre_v2_state() == SPECTRE_UNAFFECTED) {
+ val &= ~ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_CSV2);
+ val |= FIELD_PREP(ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_CSV2), 1);
+ }
+ if (arm64_get_meltdown_state() == SPECTRE_UNAFFECTED) {
+ val &= ~ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_CSV3);
+ val |= FIELD_PREP(ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_CSV3), 1);
+ }
+
+ val &= ~ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_AMU);
+
+ return val;
+}
+
static int set_id_aa64pfr0_el1(struct kvm_vcpu *vcpu,
const struct sys_reg_desc *rd,
u64 val)
{
u8 csv2, csv3;
- u64 sval = val;
/*
* Allow AA64PFR0_EL1.CSV2 to be set from userspace as long as
@@ -232,26 +318,37 @@ static int set_id_aa64pfr0_el1(struct kvm_vcpu *vcpu,
* guest could otherwise be covered in ectoplasmic residue).
*/
csv2 = cpuid_feature_extract_unsigned_field(val, ID_AA64PFR0_EL1_CSV2_SHIFT);
- if (csv2 > 1 ||
- (csv2 && arm64_get_spectre_v2_state() != SPECTRE_UNAFFECTED))
+ if (csv2 > 1 || (csv2 && arm64_get_spectre_v2_state() != SPECTRE_UNAFFECTED))
return -EINVAL;
/* Same thing for CSV3 */
csv3 = cpuid_feature_extract_unsigned_field(val, ID_AA64PFR0_EL1_CSV3_SHIFT);
- if (csv3 > 1 ||
- (csv3 && arm64_get_meltdown_state() != SPECTRE_UNAFFECTED))
+ if (csv3 > 1 || (csv3 && arm64_get_meltdown_state() != SPECTRE_UNAFFECTED))
return -EINVAL;
- /* We can only differ with CSV[23], and anything else is an error */
- val ^= read_id_reg(vcpu, rd);
- val &= ~(ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_CSV2) |
- ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_CSV3));
- if (val)
- return -EINVAL;
+ return set_id_reg(vcpu, rd, val);
+}
- IDREG(vcpu->kvm, reg_to_encoding(rd)) = sval;
+static u64 read_sanitised_id_aa64dfr0_el1(const struct id_reg_desc *idr)
+{
+ u64 val;
+ u32 id = reg_to_encoding(&idr->reg_desc);
- return 0;
+ val = read_sanitised_ftr_reg(id);
+ /* Limit debug to ARMv8.0 */
+ val &= ~ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_DebugVer);
+ val |= FIELD_PREP(ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_DebugVer), 6);
+ /*
+ * Initialise the default PMUver before there is a chance to
+ * create an actual PMU.
+ */
+ val &= ~ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_PMUVer);
+ val |= FIELD_PREP(ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_PMUVer),
+ kvm_arm_pmu_get_pmuver_limit());
+ /* Hide SPE from guests */
+ val &= ~ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_PMSVer);
+
+ return val;
}
static int set_id_aa64dfr0_el1(struct kvm_vcpu *vcpu,
@@ -260,6 +357,7 @@ static int set_id_aa64dfr0_el1(struct kvm_vcpu *vcpu,
{
u8 pmuver, host_pmuver;
bool valid_pmu;
+ int ret;
host_pmuver = kvm_arm_pmu_get_pmuver_limit();
@@ -279,23 +377,25 @@ static int set_id_aa64dfr0_el1(struct kvm_vcpu *vcpu,
if (kvm_vcpu_has_pmu(vcpu) != valid_pmu)
return -EINVAL;
- /* We can only differ with PMUver, and anything else is an error */
- val ^= read_id_reg(vcpu, rd);
- val &= ~ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_PMUVer);
- if (val)
- return -EINVAL;
-
if (valid_pmu) {
mutex_lock(&vcpu->kvm->arch.config_lock);
- IDREG(vcpu->kvm, SYS_ID_AA64DFR0_EL1) &= ~ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_PMUVer);
- IDREG(vcpu->kvm, SYS_ID_AA64DFR0_EL1) |=
- FIELD_PREP(ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_PMUVer), pmuver);
+ ret = set_id_reg(vcpu, rd, val);
+ if (ret) {
+ mutex_unlock(&vcpu->kvm->arch.config_lock);
+ return ret;
+ }
IDREG(vcpu->kvm, SYS_ID_DFR0_EL1) &= ~ARM64_FEATURE_MASK(ID_DFR0_EL1_PerfMon);
IDREG(vcpu->kvm, SYS_ID_DFR0_EL1) |=
FIELD_PREP(ARM64_FEATURE_MASK(ID_DFR0_EL1_PerfMon), pmuver_to_perfmon(pmuver));
mutex_unlock(&vcpu->kvm->arch.config_lock);
} else {
+ /* We can only differ with PMUver, and anything else is an error */
+ val ^= read_id_reg(vcpu, rd);
+ val &= ~ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_PMUVer);
+ if (val)
+ return -EINVAL;
+
assign_bit(KVM_ARCH_FLAG_VCPU_HAS_IMP_DEF_PMU, &vcpu->kvm->arch.flags,
pmuver == ID_AA64DFR0_EL1_PMUVer_IMP_DEF);
}
@@ -303,12 +403,29 @@ static int set_id_aa64dfr0_el1(struct kvm_vcpu *vcpu,
return 0;
}
+static u64 read_sanitised_id_dfr0_el1(const struct id_reg_desc *idr)
+{
+ u64 val;
+ u32 id = reg_to_encoding(&idr->reg_desc);
+
+ val = read_sanitised_ftr_reg(id);
+ /*
+ * Initialise the default PMUver before there is a chance to
+ * create an actual PMU.
+ */
+ val &= ~ARM64_FEATURE_MASK(ID_DFR0_EL1_PerfMon);
+ val |= FIELD_PREP(ARM64_FEATURE_MASK(ID_DFR0_EL1_PerfMon), kvm_arm_pmu_get_pmuver_limit());
+
+ return val;
+}
+
static int set_id_dfr0_el1(struct kvm_vcpu *vcpu,
const struct sys_reg_desc *rd,
u64 val)
{
u8 perfmon, host_perfmon;
bool valid_pmu;
+ int ret;
host_perfmon = pmuver_to_perfmon(kvm_arm_pmu_get_pmuver_limit());
@@ -329,23 +446,25 @@ static int set_id_dfr0_el1(struct kvm_vcpu *vcpu,
if (kvm_vcpu_has_pmu(vcpu) != valid_pmu)
return -EINVAL;
- /* We can only differ with PerfMon, and anything else is an error */
- val ^= read_id_reg(vcpu, rd);
- val &= ~ARM64_FEATURE_MASK(ID_DFR0_EL1_PerfMon);
- if (val)
- return -EINVAL;
-
if (valid_pmu) {
mutex_lock(&vcpu->kvm->arch.config_lock);
- IDREG(vcpu->kvm, SYS_ID_DFR0_EL1) &= ~ARM64_FEATURE_MASK(ID_DFR0_EL1_PerfMon);
- IDREG(vcpu->kvm, SYS_ID_DFR0_EL1) |=
- FIELD_PREP(ARM64_FEATURE_MASK(ID_DFR0_EL1_PerfMon), perfmon);
+ ret = set_id_reg(vcpu, rd, val);
+ if (ret) {
+ mutex_unlock(&vcpu->kvm->arch.config_lock);
+ return ret;
+ }
IDREG(vcpu->kvm, SYS_ID_AA64DFR0_EL1) &= ~ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_PMUVer);
IDREG(vcpu->kvm, SYS_ID_AA64DFR0_EL1) |=
FIELD_PREP(ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_PMUVer), perfmon_to_pmuver(perfmon));
mutex_unlock(&vcpu->kvm->arch.config_lock);
} else {
+ /* We can only differ with PerfMon, and anything else is an error */
+ val ^= read_id_reg(vcpu, rd);
+ val &= ~ARM64_FEATURE_MASK(ID_DFR0_EL1_PerfMon);
+ if (val)
+ return -EINVAL;
+
assign_bit(KVM_ARCH_FLAG_VCPU_HAS_IMP_DEF_PMU, &vcpu->kvm->arch.flags,
perfmon == ID_DFR0_EL1_PerfMon_IMPDEF);
}
@@ -354,14 +473,16 @@ static int set_id_dfr0_el1(struct kvm_vcpu *vcpu,
}
/* sys_reg_desc initialiser for known cpufeature ID registers */
+#define SYS_DESC_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, \
- }, \
+ .reg_desc = SYS_DESC_SANITISED(name), \
.ftr_bits = NULL, \
.writable_mask = 0, \
.read_kvm_sanitised_reg = general_read_kvm_sanitised_reg, \
@@ -417,7 +538,7 @@ static int set_id_dfr0_el1(struct kvm_vcpu *vcpu,
.read_kvm_sanitised_reg = NULL, \
}
-static const struct id_reg_desc id_reg_descs[KVM_ARM_ID_REG_NUM] = {
+static 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[].
@@ -433,6 +554,9 @@ static const struct id_reg_desc id_reg_descs[KVM_ARM_ID_REG_NUM] = {
.get_user = get_id_reg,
.set_user = set_id_dfr0_el1,
.visibility = aa32_id_visibility, },
+ .ftr_bits = ftr_id_dfr0,
+ .writable_mask = ID_DFR0_EL1_PerfMon_MASK,
+ .read_kvm_sanitised_reg = read_sanitised_id_dfr0_el1,
},
ID_HIDDEN(ID_AFR0_EL1),
AA32_ID_SANITISED(ID_MMFR0_EL1),
@@ -467,6 +591,9 @@ static const struct id_reg_desc id_reg_descs[KVM_ARM_ID_REG_NUM] = {
.access = access_id_reg,
.get_user = get_id_reg,
.set_user = set_id_aa64pfr0_el1, },
+ .ftr_bits = ftr_id_aa64pfr0,
+ .writable_mask = ID_AA64PFR0_EL1_CSV2_MASK | ID_AA64PFR0_EL1_CSV3_MASK,
+ .read_kvm_sanitised_reg = read_sanitised_id_aa64pfr0_el1,
},
ID_SANITISED(ID_AA64PFR1_EL1),
ID_UNALLOCATED(4, 2),
@@ -482,6 +609,9 @@ static const struct id_reg_desc id_reg_descs[KVM_ARM_ID_REG_NUM] = {
.access = access_id_reg,
.get_user = get_id_reg,
.set_user = set_id_aa64dfr0_el1, },
+ .ftr_bits = ftr_id_aa64dfr0,
+ .writable_mask = ID_AA64DFR0_EL1_PMUVer_MASK,
+ .read_kvm_sanitised_reg = read_sanitised_id_aa64dfr0_el1,
},
ID_SANITISED(ID_AA64DFR1_EL1),
ID_UNALLOCATED(5, 2),
@@ -607,7 +737,7 @@ int kvm_arm_set_id_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
return ret;
}
-bool kvm_arm_check_idreg_table(void)
+bool kvm_arm_idreg_table_init(void)
{
unsigned int i;
@@ -641,10 +771,7 @@ int kvm_arm_walk_id_regs(struct kvm_vcpu *vcpu, u64 __user *uind)
return total;
}
-/*
- * Set the guest's ID registers that are defined in id_reg_descs[]
- * with ID_SANITISED() to the host's sanitized value.
- */
+/* Initialize the guest's ID registers with KVM sanitised values. */
void kvm_arm_init_id_regs(struct kvm *kvm)
{
int i;
@@ -660,33 +787,4 @@ void kvm_arm_init_id_regs(struct kvm *kvm)
IDREG(kvm, id) = val;
}
-
- /*
- * The default is to expose CSV2 == 1 if the HW isn't affected.
- * Although this is a per-CPU feature, we make it global because
- * asymmetric systems are just a nuisance.
- *
- * Userspace can override this as long as it doesn't promise
- * the impossible.
- */
- val = IDREG(kvm, SYS_ID_AA64PFR0_EL1);
-
- if (arm64_get_spectre_v2_state() == SPECTRE_UNAFFECTED) {
- val &= ~ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_CSV2);
- val |= FIELD_PREP(ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_CSV2), 1);
- }
- if (arm64_get_meltdown_state() == SPECTRE_UNAFFECTED) {
- val &= ~ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_CSV3);
- val |= FIELD_PREP(ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_CSV3), 1);
- }
-
- IDREG(kvm, SYS_ID_AA64PFR0_EL1) = val;
-
- /*
- * Initialise the default PMUver before there is a chance to
- * create an actual PMU.
- */
- IDREG(kvm, SYS_ID_AA64DFR0_EL1) &= ~ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_PMUVer);
- IDREG(kvm, SYS_ID_AA64DFR0_EL1) |=
- FIELD_PREP(ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_PMUVer), kvm_arm_pmu_get_pmuver_limit());
}
diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index 1d7fb0acf154..27cff8022754 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -2940,14 +2940,13 @@ int __init kvm_sys_reg_table_init(void)
unsigned int i;
/* Make sure tables are unique and in order. */
- valid &= kvm_arm_check_idreg_table();
valid &= check_sysreg_table(sys_reg_descs, ARRAY_SIZE(sys_reg_descs), false);
valid &= check_sysreg_table(cp14_regs, ARRAY_SIZE(cp14_regs), true);
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 &= kvm_arm_idreg_table_init();
if (!valid)
return -EINVAL;
diff --git a/arch/arm64/kvm/sys_regs.h b/arch/arm64/kvm/sys_regs.h
index 15a0a1e2fe99..df8d26df93ec 100644
--- a/arch/arm64/kvm/sys_regs.h
+++ b/arch/arm64/kvm/sys_regs.h
@@ -246,7 +246,7 @@ int walk_one_sys_reg(const struct kvm_vcpu *vcpu,
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);
int kvm_arm_set_id_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg);
-bool kvm_arm_check_idreg_table(void);
+bool kvm_arm_idreg_table_init(void);
int kvm_arm_walk_id_regs(struct kvm_vcpu *vcpu, u64 __user *uind);
u64 kvm_arm_read_id_reg(const struct kvm_vcpu *vcpu, u32 id);
--
2.40.0.348.gf938b09366-goog
^ permalink raw reply related [flat|nested] 13+ messages in thread
* Re: [PATCH v5 0/6] Support writable CPU ID registers from userspace
2023-04-02 18:37 [PATCH v5 0/6] Support writable CPU ID registers from userspace Jing Zhang
` (5 preceding siblings ...)
2023-04-02 18:37 ` [PATCH v5 6/6] KVM: arm64: Refactor writings for PMUVer/CSV2/CSV3 Jing Zhang
@ 2023-04-03 10:30 ` Marc Zyngier
2023-04-03 19:42 ` Jing Zhang
6 siblings, 1 reply; 13+ messages in thread
From: Marc Zyngier @ 2023-04-03 10:30 UTC (permalink / raw)
To: Jing Zhang
Cc: KVM, KVMARM, ARMLinux, Oliver Upton, Will Deacon, Paolo Bonzini,
James Morse, Alexandru Elisei, Suzuki K Poulose, Fuad Tabba,
Reiji Watanabe, Raghavendra Rao Ananta
On Sun, 02 Apr 2023 19:37:29 +0100,
Jing Zhang <jingzhangos@google.com> wrote:
>
> This patchset refactors/adds code to support writable per guest CPU ID feature
> registers. Part of the code/ideas are from
> https://lore.kernel.org/all/20220419065544.3616948-1-reijiw@google.com .
> No functional change is intended in this patchset. With the new CPU ID feature
> registers infrastructure, only writtings of ID_AA64PFR0_EL1.[CSV2|CSV3],
> ID_AA64DFR0_EL1.PMUVer and ID_DFR0_ELF.PerfMon are allowed as KVM does before.
>
> Writable (Configurable) per guest CPU ID feature registers are useful for
> creating/migrating guest on ARM CPUs with different kinds of features.
>
> ---
>
> * v4 -> v5
> - Rebased to 2fad20ae05cb (kvmarm/next)
> Merge branch kvm-arm64/selftest/misc-6,4 into kvmarm-master/next
Please don't do that. Always use a stable, tagged commit, not some
random "commit of the day". If there is a dependency, indicate the
*exact* dependency. Yes, x86 is managed differently.
I'm never going to apply anything on top of an arbitrary commit, so
this makes it difficult for both you and I. I understand that you want
to avoid conflicts, but I really don't mind resolving those.
So please stick to existing tags as a base, and describe the
dependencies you have (in this case, the locking series).
Thanks,
M.
--
Without deviation from the norm, progress is not possible.
^ permalink raw reply [flat|nested] 13+ messages in thread
* Re: [PATCH v5 5/6] KVM: arm64: Introduce ID register specific descriptor
2023-04-02 18:37 ` [PATCH v5 5/6] KVM: arm64: Introduce ID register specific descriptor Jing Zhang
@ 2023-04-03 12:27 ` Marc Zyngier
2023-04-03 19:45 ` Jing Zhang
0 siblings, 1 reply; 13+ messages in thread
From: Marc Zyngier @ 2023-04-03 12:27 UTC (permalink / raw)
To: Jing Zhang
Cc: KVM, KVMARM, ARMLinux, Oliver Upton, Will Deacon, Paolo Bonzini,
James Morse, Alexandru Elisei, Suzuki K Poulose, Fuad Tabba,
Reiji Watanabe, Raghavendra Rao Ananta
On Sun, 02 Apr 2023 19:37:34 +0100,
Jing Zhang <jingzhangos@google.com> wrote:
>
> 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@google.com>
> Signed-off-by: Reiji Watanabe <reijiw@google.com>
> Signed-off-by: Jing Zhang <jingzhangos@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;
Why do we need to keep this around? we already have all the required
infrastructure to lookup a full arm64_ftr_reg. So why the added stuff?
> + /*
> + * 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);
Why can't this function return both the required value and a mask?
Why can't it live in the sys_reg_desc structure?
Frankly, I don't see a good reason to have this wrapper structure
which makes things pointlessly complicated and prevent code sharing
with the rest of the infrastructure.
M.
--
Without deviation from the norm, progress is not possible.
^ permalink raw reply [flat|nested] 13+ messages in thread
* Re: [PATCH v5 6/6] KVM: arm64: Refactor writings for PMUVer/CSV2/CSV3
2023-04-02 18:37 ` [PATCH v5 6/6] KVM: arm64: Refactor writings for PMUVer/CSV2/CSV3 Jing Zhang
@ 2023-04-03 14:55 ` Marc Zyngier
2023-04-03 19:50 ` Jing Zhang
0 siblings, 1 reply; 13+ messages in thread
From: Marc Zyngier @ 2023-04-03 14:55 UTC (permalink / raw)
To: Jing Zhang
Cc: KVM, KVMARM, ARMLinux, Oliver Upton, Will Deacon, Paolo Bonzini,
James Morse, Alexandru Elisei, Suzuki K Poulose, Fuad Tabba,
Reiji Watanabe, Raghavendra Rao Ananta
On Sun, 02 Apr 2023 19:37:35 +0100,
Jing Zhang <jingzhangos@google.com> wrote:
>
> Refactor writings for ID_AA64PFR0_EL1.[CSV2|CSV3],
> ID_AA64DFR0_EL1.PMUVer and ID_DFR0_ELF.PerfMon based on utilities
> introduced by ID register descriptor.
>
> No functional change intended.
>
> Co-developed-by: Reiji Watanabe <reijiw@google.com>
> Signed-off-by: Reiji Watanabe <reijiw@google.com>
> Signed-off-by: Jing Zhang <jingzhangos@google.com>
> ---
> arch/arm64/include/asm/cpufeature.h | 5 +
> arch/arm64/kernel/cpufeature.c | 8 +-
> arch/arm64/kvm/id_regs.c | 262 +++++++++++++++++++---------
> arch/arm64/kvm/sys_regs.c | 3 +-
> arch/arm64/kvm/sys_regs.h | 2 +-
> 5 files changed, 191 insertions(+), 89 deletions(-)
>
> diff --git a/arch/arm64/include/asm/cpufeature.h b/arch/arm64/include/asm/cpufeature.h
> index 6bf013fb110d..f17e74afe3e9 100644
> --- a/arch/arm64/include/asm/cpufeature.h
> +++ b/arch/arm64/include/asm/cpufeature.h
> @@ -915,6 +915,7 @@ static inline unsigned int get_vmid_bits(u64 mmfr1)
> return 8;
> }
>
> +s64 arm64_ftr_safe_value(const struct arm64_ftr_bits *ftrp, s64 new, s64 cur);
> struct arm64_ftr_reg *get_arm64_ftr_reg(u32 sys_id);
>
> extern struct arm64_ftr_override id_aa64mmfr1_override;
> @@ -925,6 +926,10 @@ extern struct arm64_ftr_override id_aa64smfr0_override;
> extern struct arm64_ftr_override id_aa64isar1_override;
> extern struct arm64_ftr_override id_aa64isar2_override;
>
> +extern const struct arm64_ftr_bits ftr_id_dfr0[];
> +extern const struct arm64_ftr_bits ftr_id_aa64pfr0[];
> +extern const struct arm64_ftr_bits ftr_id_aa64dfr0[];
> +
> u32 get_kvm_ipa_limit(void);
> void dump_cpu_features(void);
>
> diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
> index c331c49a7d19..5b0e3379e5f8 100644
> --- a/arch/arm64/kernel/cpufeature.c
> +++ b/arch/arm64/kernel/cpufeature.c
> @@ -225,7 +225,7 @@ static const struct arm64_ftr_bits ftr_id_aa64isar2[] = {
> ARM64_FTR_END,
> };
>
> -static const struct arm64_ftr_bits ftr_id_aa64pfr0[] = {
> +const struct arm64_ftr_bits ftr_id_aa64pfr0[] = {
> ARM64_FTR_BITS(FTR_HIDDEN, FTR_NONSTRICT, FTR_LOWER_SAFE, ID_AA64PFR0_EL1_CSV3_SHIFT, 4, 0),
> ARM64_FTR_BITS(FTR_HIDDEN, FTR_NONSTRICT, FTR_LOWER_SAFE, ID_AA64PFR0_EL1_CSV2_SHIFT, 4, 0),
> ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64PFR0_EL1_DIT_SHIFT, 4, 0),
> @@ -426,7 +426,7 @@ static const struct arm64_ftr_bits ftr_id_mmfr0[] = {
> ARM64_FTR_END,
> };
>
> -static const struct arm64_ftr_bits ftr_id_aa64dfr0[] = {
> +const struct arm64_ftr_bits ftr_id_aa64dfr0[] = {
> S_ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64DFR0_EL1_DoubleLock_SHIFT, 4, 0),
> ARM64_FTR_BITS(FTR_HIDDEN, FTR_NONSTRICT, FTR_LOWER_SAFE, ID_AA64DFR0_EL1_PMSVer_SHIFT, 4, 0),
> ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64DFR0_EL1_CTX_CMPs_SHIFT, 4, 0),
> @@ -578,7 +578,7 @@ static const struct arm64_ftr_bits ftr_id_pfr2[] = {
> ARM64_FTR_END,
> };
>
> -static const struct arm64_ftr_bits ftr_id_dfr0[] = {
> +const struct arm64_ftr_bits ftr_id_dfr0[] = {
> /* [31:28] TraceFilt */
> S_ARM64_FTR_BITS(FTR_HIDDEN, FTR_NONSTRICT, FTR_EXACT, ID_DFR0_EL1_PerfMon_SHIFT, 4, 0),
> ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_DFR0_EL1_MProfDbg_SHIFT, 4, 0),
There really isn't a good reason for exposing any of this. You can
readily get to the overarching arm64_ftr_reg.
> @@ -791,7 +791,7 @@ static u64 arm64_ftr_set_value(const struct arm64_ftr_bits *ftrp, s64 reg,
> return reg;
> }
>
> -static s64 arm64_ftr_safe_value(const struct arm64_ftr_bits *ftrp, s64 new,
> +s64 arm64_ftr_safe_value(const struct arm64_ftr_bits *ftrp, s64 new,
> s64 cur)
> {
> s64 ret = 0;
> diff --git a/arch/arm64/kvm/id_regs.c b/arch/arm64/kvm/id_regs.c
> index af86001e2686..395eaf84a0ab 100644
> --- a/arch/arm64/kvm/id_regs.c
> +++ b/arch/arm64/kvm/id_regs.c
> @@ -39,6 +39,64 @@ struct id_reg_desc {
> u64 (*read_kvm_sanitised_reg)(const struct id_reg_desc *idr);
> };
>
> +static struct id_reg_desc id_reg_descs[];
> +
> +/**
> + * arm64_check_features() - Check if a feature register value constitutes
> + * a subset of features indicated by @limit.
> + *
> + * @ftrp: Pointer to an array of arm64_ftr_bits. It must be terminated by
> + * an item whose width field is zero.
> + * @writable_mask: Indicates writable feature bits.
> + * @val: The feature register value to check
> + * @limit: The limit value of the feature register
> + *
> + * This function will check if each feature field of @val is the "safe" value
> + * against @limit based on @ftrp[], each of which specifies the target field
> + * (shift, width), whether or not the field is for a signed value (sign),
> + * how the field is determined to be "safe" (type), and the safe value
> + * (safe_val) when type == FTR_EXACT (safe_val won't be used by this
> + * function when type != FTR_EXACT). Any other fields in arm64_ftr_bits
> + * won't be used by this function. If a field value in @val is the same
> + * as the one in @limit, it is always considered the safe value regardless
> + * of the type. For register fields that are not in writable, only the value
> + * in @limit is considered the safe value.
> + *
> + * Return: 0 if all the fields are safe. Otherwise, return negative errno.
> + */
> +static int arm64_check_features(const struct arm64_ftr_bits *ftrp,
> + u64 writable_mask, u64 val, u64 limit)
> +{
> + u64 mask = 0;
> +
> + for (; ftrp && ftrp->width; ftrp++) {
> + s64 f_val, f_lim, safe_val;
> + u64 ftr_mask;
> +
> + ftr_mask = arm64_ftr_mask(ftrp);
> + if ((ftr_mask & writable_mask) != ftr_mask)
> + continue;
> +
> + f_val = arm64_ftr_value(ftrp, val);
> + f_lim = arm64_ftr_value(ftrp, limit);
> + mask |= ftr_mask;
> +
> + if (f_val == f_lim)
> + safe_val = f_val;
> + else
> + safe_val = arm64_ftr_safe_value(ftrp, f_val, f_lim);
> +
> + if (safe_val != f_val)
> + return -E2BIG;
> + }
> +
> + /* For fields that are not writable, values in limit are the safe values. */
> + if ((val & ~mask) != (limit & ~mask))
> + return -E2BIG;
> +
> + return 0;
> +}
> +
> static u8 vcpu_pmuver(const struct kvm_vcpu *vcpu)
> {
> if (kvm_vcpu_has_pmu(vcpu))
> @@ -84,7 +142,6 @@ u64 kvm_arm_read_id_reg(const struct kvm_vcpu *vcpu, u32 id)
> case SYS_ID_AA64PFR0_EL1:
> if (!vcpu_has_sve(vcpu))
> val &= ~ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_SVE);
> - val &= ~ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_AMU);
> if (kvm_vgic_global_state.type == VGIC_V3) {
> val &= ~ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_GIC);
> val |= FIELD_PREP(ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_GIC), 1);
> @@ -111,15 +168,10 @@ u64 kvm_arm_read_id_reg(const struct kvm_vcpu *vcpu, u32 id)
> val &= ~ARM64_FEATURE_MASK(ID_AA64ISAR2_EL1_WFxT);
> break;
> case SYS_ID_AA64DFR0_EL1:
> - /* Limit debug to ARMv8.0 */
> - val &= ~ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_DebugVer);
> - val |= FIELD_PREP(ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_DebugVer), 6);
> /* Set PMUver to the required version */
> val &= ~ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_PMUVer);
> val |= FIELD_PREP(ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_PMUVer),
> vcpu_pmuver(vcpu));
> - /* Hide SPE from guests */
> - val &= ~ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_PMSVer);
> break;
> case SYS_ID_DFR0_EL1:
> val &= ~ARM64_FEATURE_MASK(ID_DFR0_EL1_PerfMon);
> @@ -178,9 +230,16 @@ static int get_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,
> u64 val)
> {
> - /* This is what we mean by invariant: you can't change it. */
> - if (val != read_id_reg(vcpu, rd))
> - return -EINVAL;
> + int ret;
> + int id = reg_to_encoding(rd);
> + const struct id_reg_desc *idr = &id_reg_descs[IDREG_IDX(id)];
> +
> + ret = arm64_check_features(idr->ftr_bits, idr->writable_mask, val,
> + idr->read_kvm_sanitised_reg ? idr->read_kvm_sanitised_reg(idr) : 0);
> + if (ret)
> + return ret;
> +
> + IDREG(vcpu->kvm, id) = val;
>
> return 0;
> }
> @@ -219,12 +278,39 @@ 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 u64 read_sanitised_id_aa64pfr0_el1(const struct id_reg_desc *idr)
> +{
> + u64 val;
> + u32 id = reg_to_encoding(&idr->reg_desc);
> +
> + val = read_sanitised_ftr_reg(id);
> + /*
> + * The default is to expose CSV2 == 1 if the HW isn't affected.
> + * Although this is a per-CPU feature, we make it global because
> + * asymmetric systems are just a nuisance.
> + *
> + * Userspace can override this as long as it doesn't promise
> + * the impossible.
> + */
> + if (arm64_get_spectre_v2_state() == SPECTRE_UNAFFECTED) {
> + val &= ~ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_CSV2);
> + val |= FIELD_PREP(ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_CSV2), 1);
> + }
> + if (arm64_get_meltdown_state() == SPECTRE_UNAFFECTED) {
> + val &= ~ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_CSV3);
> + val |= FIELD_PREP(ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_CSV3), 1);
> + }
> +
> + val &= ~ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_AMU);
> +
> + return val;
> +}
> +
> static int set_id_aa64pfr0_el1(struct kvm_vcpu *vcpu,
> const struct sys_reg_desc *rd,
> u64 val)
> {
> u8 csv2, csv3;
> - u64 sval = val;
>
> /*
> * Allow AA64PFR0_EL1.CSV2 to be set from userspace as long as
> @@ -232,26 +318,37 @@ static int set_id_aa64pfr0_el1(struct kvm_vcpu *vcpu,
> * guest could otherwise be covered in ectoplasmic residue).
> */
> csv2 = cpuid_feature_extract_unsigned_field(val, ID_AA64PFR0_EL1_CSV2_SHIFT);
> - if (csv2 > 1 ||
> - (csv2 && arm64_get_spectre_v2_state() != SPECTRE_UNAFFECTED))
> + if (csv2 > 1 || (csv2 && arm64_get_spectre_v2_state() != SPECTRE_UNAFFECTED))
> return -EINVAL;
>
> /* Same thing for CSV3 */
> csv3 = cpuid_feature_extract_unsigned_field(val, ID_AA64PFR0_EL1_CSV3_SHIFT);
> - if (csv3 > 1 ||
> - (csv3 && arm64_get_meltdown_state() != SPECTRE_UNAFFECTED))
> + if (csv3 > 1 || (csv3 && arm64_get_meltdown_state() != SPECTRE_UNAFFECTED))
> return -EINVAL;
>
> - /* We can only differ with CSV[23], and anything else is an error */
> - val ^= read_id_reg(vcpu, rd);
> - val &= ~(ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_CSV2) |
> - ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_CSV3));
> - if (val)
> - return -EINVAL;
> + return set_id_reg(vcpu, rd, val);
> +}
>
> - IDREG(vcpu->kvm, reg_to_encoding(rd)) = sval;
> +static u64 read_sanitised_id_aa64dfr0_el1(const struct id_reg_desc *idr)
> +{
> + u64 val;
> + u32 id = reg_to_encoding(&idr->reg_desc);
>
> - return 0;
> + val = read_sanitised_ftr_reg(id);
> + /* Limit debug to ARMv8.0 */
> + val &= ~ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_DebugVer);
> + val |= FIELD_PREP(ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_DebugVer), 6);
> + /*
> + * Initialise the default PMUver before there is a chance to
> + * create an actual PMU.
> + */
> + val &= ~ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_PMUVer);
> + val |= FIELD_PREP(ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_PMUVer),
> + kvm_arm_pmu_get_pmuver_limit());
> + /* Hide SPE from guests */
> + val &= ~ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_PMSVer);
> +
> + return val;
> }
>
> static int set_id_aa64dfr0_el1(struct kvm_vcpu *vcpu,
> @@ -260,6 +357,7 @@ static int set_id_aa64dfr0_el1(struct kvm_vcpu *vcpu,
> {
> u8 pmuver, host_pmuver;
> bool valid_pmu;
> + int ret;
>
> host_pmuver = kvm_arm_pmu_get_pmuver_limit();
>
> @@ -279,23 +377,25 @@ static int set_id_aa64dfr0_el1(struct kvm_vcpu *vcpu,
> if (kvm_vcpu_has_pmu(vcpu) != valid_pmu)
> return -EINVAL;
>
> - /* We can only differ with PMUver, and anything else is an error */
> - val ^= read_id_reg(vcpu, rd);
> - val &= ~ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_PMUVer);
> - if (val)
> - return -EINVAL;
> -
> if (valid_pmu) {
> mutex_lock(&vcpu->kvm->arch.config_lock);
> - IDREG(vcpu->kvm, SYS_ID_AA64DFR0_EL1) &= ~ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_PMUVer);
> - IDREG(vcpu->kvm, SYS_ID_AA64DFR0_EL1) |=
> - FIELD_PREP(ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_PMUVer), pmuver);
> + ret = set_id_reg(vcpu, rd, val);
> + if (ret) {
> + mutex_unlock(&vcpu->kvm->arch.config_lock);
> + return ret;
> + }
>
> IDREG(vcpu->kvm, SYS_ID_DFR0_EL1) &= ~ARM64_FEATURE_MASK(ID_DFR0_EL1_PerfMon);
> IDREG(vcpu->kvm, SYS_ID_DFR0_EL1) |=
> FIELD_PREP(ARM64_FEATURE_MASK(ID_DFR0_EL1_PerfMon), pmuver_to_perfmon(pmuver));
I repeatedly asked for assignments to be *on a single line*.
> mutex_unlock(&vcpu->kvm->arch.config_lock);
> } else {
> + /* We can only differ with PMUver, and anything else is an error */
> + val ^= read_id_reg(vcpu, rd);
> + val &= ~ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_PMUVer);
> + if (val)
> + return -EINVAL;
> +
I asked about this before. Why do we need this? Isn't the whole point
of the exercise to have a *unified* way to check for the writable
bits? If you still need to open-code that, the whole exercise is a
bit pointless, isn't it?
Frankly, the whole thing is going the wrong way, starting with the
wrapping data structure. We already have most of what we need in
sys_reg_desc, and it only takes a bit of imagination to get there.
I've spent a couple of hours hacking away at the series, and got rid
of it entirely, simply by repurposing exist fields (val for the write
mask, reset for the limit value). All I can say is that it compiles.
But at least it doesn't reinvent the wheel.
M.
diff --git a/arch/arm64/kvm/id_regs.c b/arch/arm64/kvm/id_regs.c
index 395eaf84a0ab..30f36e0dd12e 100644
--- a/arch/arm64/kvm/id_regs.c
+++ b/arch/arm64/kvm/id_regs.c
@@ -18,29 +18,6 @@
#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 struct id_reg_desc id_reg_descs[];
-
/**
* arm64_check_features() - Check if a feature register value constitutes
* a subset of features indicated by @limit.
@@ -64,11 +41,26 @@ static struct id_reg_desc id_reg_descs[];
*
* Return: 0 if all the fields are safe. Otherwise, return negative errno.
*/
-static int arm64_check_features(const struct arm64_ftr_bits *ftrp,
- u64 writable_mask, u64 val, u64 limit)
+static int arm64_check_features(struct kvm_vcpu *vcpu,
+ const struct sys_reg_desc *rd,
+ u64 val)
{
+ const struct arm64_ftr_reg *ftr_reg;
+ const struct arm64_ftr_bits *ftrp;
+ u32 id = reg_to_encoding(rd);
+ u64 writable_mask = rd->val;
+ u64 limit = 0;
u64 mask = 0;
+ if (rd->reset)
+ limit = rd->reset(vcpu, rd);
+
+ ftr_reg = get_arm64_ftr_reg(id);
+ if (!ftr_reg)
+ return -EINVAL;
+
+ ftrp = ftr_reg->ftr_bits;
+
for (; ftrp && ftrp->width; ftrp++) {
s64 f_val, f_lim, safe_val;
u64 ftr_mask;
@@ -230,12 +222,10 @@ static int get_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,
u64 val)
{
+ u32 id = reg_to_encoding(rd);
int ret;
- int id = reg_to_encoding(rd);
- const struct id_reg_desc *idr = &id_reg_descs[IDREG_IDX(id)];
- ret = arm64_check_features(idr->ftr_bits, idr->writable_mask, val,
- idr->read_kvm_sanitised_reg ? idr->read_kvm_sanitised_reg(idr) : 0);
+ ret = arm64_check_features(vcpu, rd, val);
if (ret)
return ret;
@@ -273,15 +263,17 @@ 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)
+static u64 general_read_kvm_sanitised_reg(struct kvm_vcpu *vcpu,
+ const struct sys_reg_desc *r)
{
- return read_sanitised_ftr_reg(reg_to_encoding(&idr->reg_desc));
+ return read_sanitised_ftr_reg(reg_to_encoding(r));
}
-static u64 read_sanitised_id_aa64pfr0_el1(const struct id_reg_desc *idr)
+static u64 read_sanitised_id_aa64pfr0_el1(struct kvm_vcpu *vcpu,
+ const struct sys_reg_desc *r)
{
u64 val;
- u32 id = reg_to_encoding(&idr->reg_desc);
+ u32 id = reg_to_encoding(r);
val = read_sanitised_ftr_reg(id);
/*
@@ -329,10 +321,11 @@ static int set_id_aa64pfr0_el1(struct kvm_vcpu *vcpu,
return set_id_reg(vcpu, rd, val);
}
-static u64 read_sanitised_id_aa64dfr0_el1(const struct id_reg_desc *idr)
+static u64 read_sanitised_id_aa64dfr0_el1(struct kvm_vcpu *vcpu,
+ const struct sys_reg_desc *r)
{
u64 val;
- u32 id = reg_to_encoding(&idr->reg_desc);
+ u32 id = reg_to_encoding(r);
val = read_sanitised_ftr_reg(id);
/* Limit debug to ARMv8.0 */
@@ -403,10 +396,11 @@ static int set_id_aa64dfr0_el1(struct kvm_vcpu *vcpu,
return 0;
}
-static u64 read_sanitised_id_dfr0_el1(const struct id_reg_desc *idr)
+static u64 read_sanitised_id_dfr0_el1(struct kvm_vcpu *vcpu,
+ const struct sys_reg_desc *r)
{
u64 val;
- u32 id = reg_to_encoding(&idr->reg_desc);
+ u32 id = reg_to_encoding(r);
val = read_sanitised_ftr_reg(id);
/*
@@ -473,33 +467,23 @@ static int set_id_dfr0_el1(struct kvm_vcpu *vcpu,
}
/* sys_reg_desc initialiser for known cpufeature ID registers */
-#define SYS_DESC_SANITISED(name) { \
+#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_SANITISED(name), \
- .ftr_bits = NULL, \
- .writable_mask = 0, \
- .read_kvm_sanitised_reg = general_read_kvm_sanitised_reg, \
+ .reset = general_read_kvm_sanitised_reg, \
}
/* sys_reg_desc initialiser for known cpufeature ID registers */
-#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, \
+#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, \
+ .reset = general_read_kvm_sanitised_reg, \
}
/*
@@ -508,16 +492,11 @@ static int set_id_dfr0_el1(struct kvm_vcpu *vcpu,
* (1 <= crm < 8, 0 <= Op2 < 8).
*/
#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, \
}
/*
@@ -526,19 +505,14 @@ static int set_id_dfr0_el1(struct kvm_vcpu *vcpu,
* RAZ for the guest.
*/
#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 struct id_reg_desc id_reg_descs[KVM_ARM_ID_REG_NUM] = {
+static struct sys_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[].
@@ -548,15 +522,14 @@ static struct id_reg_desc id_reg_descs[KVM_ARM_ID_REG_NUM] = {
/* CRm=1 */
AA32_ID_SANITISED(ID_PFR0_EL1),
AA32_ID_SANITISED(ID_PFR1_EL1),
- { .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, },
- .ftr_bits = ftr_id_dfr0,
- .writable_mask = ID_DFR0_EL1_PerfMon_MASK,
- .read_kvm_sanitised_reg = read_sanitised_id_dfr0_el1,
+ .visibility = aa32_id_visibility,
+ .val = ID_DFR0_EL1_PerfMon_MASK,
+ .reset = read_sanitised_id_dfr0_el1,
},
ID_HIDDEN(ID_AFR0_EL1),
AA32_ID_SANITISED(ID_MMFR0_EL1),
@@ -586,14 +559,13 @@ static struct id_reg_desc id_reg_descs[KVM_ARM_ID_REG_NUM] = {
/* AArch64 ID registers */
/* CRm=4 */
- { .reg_desc = {
+ {
SYS_DESC(SYS_ID_AA64PFR0_EL1),
.access = access_id_reg,
.get_user = get_id_reg,
- .set_user = set_id_aa64pfr0_el1, },
- .ftr_bits = ftr_id_aa64pfr0,
- .writable_mask = ID_AA64PFR0_EL1_CSV2_MASK | ID_AA64PFR0_EL1_CSV3_MASK,
- .read_kvm_sanitised_reg = read_sanitised_id_aa64pfr0_el1,
+ .set_user = set_id_aa64pfr0_el1,
+ .val = ID_AA64PFR0_EL1_CSV2_MASK | ID_AA64PFR0_EL1_CSV3_MASK,
+ .reset = read_sanitised_id_aa64pfr0_el1,
},
ID_SANITISED(ID_AA64PFR1_EL1),
ID_UNALLOCATED(4, 2),
@@ -604,14 +576,13 @@ static struct id_reg_desc id_reg_descs[KVM_ARM_ID_REG_NUM] = {
ID_UNALLOCATED(4, 7),
/* CRm=5 */
- { .reg_desc = {
+ {
SYS_DESC(SYS_ID_AA64DFR0_EL1),
.access = access_id_reg,
.get_user = get_id_reg,
- .set_user = set_id_aa64dfr0_el1, },
- .ftr_bits = ftr_id_aa64dfr0,
- .writable_mask = ID_AA64DFR0_EL1_PMUVer_MASK,
- .read_kvm_sanitised_reg = read_sanitised_id_aa64dfr0_el1,
+ .set_user = set_id_aa64dfr0_el1,
+ .val = ID_AA64DFR0_EL1_PMUVer_MASK,
+ .reset = read_sanitised_id_aa64dfr0_el1,
},
ID_SANITISED(ID_AA64DFR1_EL1),
ID_UNALLOCATED(5, 2),
@@ -648,7 +619,7 @@ static const struct sys_reg_desc *id_params_to_desc(struct sys_reg_params *param
id = reg_to_encoding(params);
if (is_id_reg(id))
- return &id_reg_descs[IDREG_IDX(id)].reg_desc;
+ return &id_reg_descs[IDREG_IDX(id)];
return NULL;
}
@@ -742,11 +713,11 @@ bool kvm_arm_idreg_table_init(void)
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;
+ const struct sys_reg_desc *r = &id_reg_descs[i];
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);
+ id_reg_descs, i);
return false;
}
}
@@ -756,7 +727,7 @@ bool kvm_arm_idreg_table_init(void)
int kvm_arm_walk_id_regs(struct kvm_vcpu *vcpu, u64 __user *uind)
{
- const struct id_reg_desc *i2, *end2;
+ const struct sys_reg_desc *i2, *end2;
unsigned int total = 0;
int err;
@@ -764,7 +735,7 @@ int kvm_arm_walk_id_regs(struct kvm_vcpu *vcpu, u64 __user *uind)
end2 = id_reg_descs + ARRAY_SIZE(id_reg_descs);
for (; i2 != end2; i2++) {
- err = walk_one_sys_reg(vcpu, &(i2->reg_desc), &uind, &total);
+ err = walk_one_sys_reg(vcpu, i2, &uind, &total);
if (err)
return err;
}
@@ -779,11 +750,11 @@ 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].reg_desc);
+ id = reg_to_encoding(&id_reg_descs[i]);
val = 0;
- if (id_reg_descs[i].read_kvm_sanitised_reg)
- val = id_reg_descs[i].read_kvm_sanitised_reg(&id_reg_descs[i]);
+ if (id_reg_descs[i].reset)
+ val = id_reg_descs[i].reset(NULL, &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 b90d1d3ad081..c4f498e75315 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -540,10 +540,11 @@ static int get_bvr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
return 0;
}
-static void reset_bvr(struct kvm_vcpu *vcpu,
+static u64 reset_bvr(struct kvm_vcpu *vcpu,
const struct sys_reg_desc *rd)
{
vcpu->arch.vcpu_debug_state.dbg_bvr[rd->CRm] = rd->val;
+ return rd->val;
}
static bool trap_bcr(struct kvm_vcpu *vcpu,
@@ -576,10 +577,11 @@ static int get_bcr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
return 0;
}
-static void reset_bcr(struct kvm_vcpu *vcpu,
+static u64 reset_bcr(struct kvm_vcpu *vcpu,
const struct sys_reg_desc *rd)
{
vcpu->arch.vcpu_debug_state.dbg_bcr[rd->CRm] = rd->val;
+ return rd->val;
}
static bool trap_wvr(struct kvm_vcpu *vcpu,
@@ -613,10 +615,11 @@ static int get_wvr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
return 0;
}
-static void reset_wvr(struct kvm_vcpu *vcpu,
+static u64 reset_wvr(struct kvm_vcpu *vcpu,
const struct sys_reg_desc *rd)
{
vcpu->arch.vcpu_debug_state.dbg_wvr[rd->CRm] = rd->val;
+ return rd->val;
}
static bool trap_wcr(struct kvm_vcpu *vcpu,
@@ -649,25 +652,28 @@ static int get_wcr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
return 0;
}
-static void reset_wcr(struct kvm_vcpu *vcpu,
+static u64 reset_wcr(struct kvm_vcpu *vcpu,
const struct sys_reg_desc *rd)
{
vcpu->arch.vcpu_debug_state.dbg_wcr[rd->CRm] = rd->val;
+ return rd->val;
}
-static void reset_amair_el1(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
+static u64 reset_amair_el1(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
{
u64 amair = read_sysreg(amair_el1);
vcpu_write_sys_reg(vcpu, amair, AMAIR_EL1);
+ return amair;
}
-static void reset_actlr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
+static u64 reset_actlr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
{
u64 actlr = read_sysreg(actlr_el1);
vcpu_write_sys_reg(vcpu, actlr, ACTLR_EL1);
+ return actlr;
}
-static void reset_mpidr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
+static u64 reset_mpidr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
{
u64 mpidr;
@@ -681,7 +687,9 @@ static void reset_mpidr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
mpidr = (vcpu->vcpu_id & 0x0f) << MPIDR_LEVEL_SHIFT(0);
mpidr |= ((vcpu->vcpu_id >> 4) & 0xff) << MPIDR_LEVEL_SHIFT(1);
mpidr |= ((vcpu->vcpu_id >> 12) & 0xff) << MPIDR_LEVEL_SHIFT(2);
- vcpu_write_sys_reg(vcpu, (1ULL << 31) | mpidr, MPIDR_EL1);
+ mpidr |= (1ULL << 31);
+ vcpu_write_sys_reg(vcpu, mpidr, MPIDR_EL1);
+ return mpidr;
}
static unsigned int pmu_visibility(const struct kvm_vcpu *vcpu,
@@ -693,13 +701,13 @@ static unsigned int pmu_visibility(const struct kvm_vcpu *vcpu,
return REG_HIDDEN;
}
-static void reset_pmu_reg(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
+static u64 reset_pmu_reg(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
{
u64 n, mask = BIT(ARMV8_PMU_CYCLE_IDX);
/* No PMU available, any PMU reg may UNDEF... */
if (!kvm_arm_support_pmu_v3())
- return;
+ return 0;
n = read_sysreg(pmcr_el0) >> ARMV8_PMU_PMCR_N_SHIFT;
n &= ARMV8_PMU_PMCR_N_MASK;
@@ -708,33 +716,37 @@ static void reset_pmu_reg(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
reset_unknown(vcpu, r);
__vcpu_sys_reg(vcpu, r->reg) &= mask;
+ return __vcpu_sys_reg(vcpu, r->reg);
}
-static void reset_pmevcntr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
+static u64 reset_pmevcntr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
{
reset_unknown(vcpu, r);
__vcpu_sys_reg(vcpu, r->reg) &= GENMASK(31, 0);
+ return __vcpu_sys_reg(vcpu, r->reg);
}
-static void reset_pmevtyper(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
+static u64 reset_pmevtyper(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
{
reset_unknown(vcpu, r);
__vcpu_sys_reg(vcpu, r->reg) &= ARMV8_PMU_EVTYPE_MASK;
+ return __vcpu_sys_reg(vcpu, r->reg);
}
-static void reset_pmselr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
+static u64 reset_pmselr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
{
reset_unknown(vcpu, r);
__vcpu_sys_reg(vcpu, r->reg) &= ARMV8_PMU_COUNTER_MASK;
+ return __vcpu_sys_reg(vcpu, r->reg);
}
-static void reset_pmcr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
+static u64 reset_pmcr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
{
u64 pmcr;
/* No PMU available, PMCR_EL0 may UNDEF... */
if (!kvm_arm_support_pmu_v3())
- return;
+ return 0;
/* Only preserve PMCR_EL0.N, and reset the rest to 0 */
pmcr = read_sysreg(pmcr_el0) & (ARMV8_PMU_PMCR_N_MASK << ARMV8_PMU_PMCR_N_SHIFT);
@@ -742,6 +754,7 @@ static void reset_pmcr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
pmcr |= ARMV8_PMU_PMCR_LC;
__vcpu_sys_reg(vcpu, r->reg) = pmcr;
+ return __vcpu_sys_reg(vcpu, r->reg);
}
static bool check_pmu_access_disabled(struct kvm_vcpu *vcpu, u64 flags)
@@ -1205,7 +1218,7 @@ static bool access_clidr(struct kvm_vcpu *vcpu, struct sys_reg_params *p,
* Fabricate a CLIDR_EL1 value instead of using the real value, which can vary
* by the physical CPU which the vcpu currently resides in.
*/
-static void reset_clidr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
+static u64 reset_clidr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
{
u64 ctr_el0 = read_sanitised_ftr_reg(SYS_CTR_EL0);
u64 clidr;
@@ -1253,6 +1266,7 @@ static void reset_clidr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
clidr |= 2 << CLIDR_TTYPE_SHIFT(loc);
__vcpu_sys_reg(vcpu, r->reg) = clidr;
+ return __vcpu_sys_reg(vcpu, r->reg);
}
static int set_clidr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
@@ -2603,19 +2617,21 @@ id_to_sys_reg_desc(struct kvm_vcpu *vcpu, u64 id,
*/
#define FUNCTION_INVARIANT(reg) \
- static void get_##reg(struct kvm_vcpu *v, \
+ static u64 get_##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(midr_el1)
FUNCTION_INVARIANT(revidr_el1)
FUNCTION_INVARIANT(aidr_el1)
-static void get_ctr_el0(struct kvm_vcpu *v, const struct sys_reg_desc *r)
+static u64 get_ctr_el0(struct kvm_vcpu *v, const struct sys_reg_desc *r)
{
((struct sys_reg_desc *)r)->val = read_sanitised_ftr_reg(SYS_CTR_EL0);
+ return ((struct sys_reg_desc *)r)->val;
}
/* ->val is filled in by kvm_sys_reg_table_init() */
diff --git a/arch/arm64/kvm/sys_regs.h b/arch/arm64/kvm/sys_regs.h
index df8d26df93ec..d14d5b41a222 100644
--- a/arch/arm64/kvm/sys_regs.h
+++ b/arch/arm64/kvm/sys_regs.h
@@ -65,12 +65,12 @@ struct sys_reg_desc {
const struct sys_reg_desc *);
/* Initialization for vcpu. */
- void (*reset)(struct kvm_vcpu *, const struct sys_reg_desc *);
+ u64 (*reset)(struct kvm_vcpu *, const struct sys_reg_desc *);
/* Index into sys_reg[], or 0 if we don't need to save it. */
int reg;
- /* Value (usually reset value) */
+ /* Value (usually reset value), or write mask for idregs */
u64 val;
/* Custom get/set_user functions, fallback to generic if NULL */
@@ -123,19 +123,21 @@ static inline bool read_zero(struct kvm_vcpu *vcpu,
}
/* Reset functions */
-static inline void reset_unknown(struct kvm_vcpu *vcpu,
+static inline u64 reset_unknown(struct kvm_vcpu *vcpu,
const struct sys_reg_desc *r)
{
BUG_ON(!r->reg);
BUG_ON(r->reg >= NR_SYS_REGS);
__vcpu_sys_reg(vcpu, r->reg) = 0x1de7ec7edbadc0deULL;
+ return __vcpu_sys_reg(vcpu, r->reg);
}
-static inline void reset_val(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
+static inline u64 reset_val(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
{
BUG_ON(!r->reg);
BUG_ON(r->reg >= NR_SYS_REGS);
__vcpu_sys_reg(vcpu, r->reg) = r->val;
+ return __vcpu_sys_reg(vcpu, r->reg);
}
static inline unsigned int sysreg_visibility(const struct kvm_vcpu *vcpu,
--
Without deviation from the norm, progress is not possible.
^ permalink raw reply related [flat|nested] 13+ messages in thread
* Re: [PATCH v5 0/6] Support writable CPU ID registers from userspace
2023-04-03 10:30 ` [PATCH v5 0/6] Support writable CPU ID registers from userspace Marc Zyngier
@ 2023-04-03 19:42 ` Jing Zhang
0 siblings, 0 replies; 13+ messages in thread
From: Jing Zhang @ 2023-04-03 19:42 UTC (permalink / raw)
To: Marc Zyngier
Cc: KVM, KVMARM, ARMLinux, Oliver Upton, Will Deacon, Paolo Bonzini,
James Morse, Alexandru Elisei, Suzuki K Poulose, Fuad Tabba,
Reiji Watanabe, Raghavendra Rao Ananta
Hi Marc,
On Mon, Apr 3, 2023 at 3:30 AM Marc Zyngier <maz@kernel.org> wrote:
>
> On Sun, 02 Apr 2023 19:37:29 +0100,
> Jing Zhang <jingzhangos@google.com> wrote:
> >
> > This patchset refactors/adds code to support writable per guest CPU ID feature
> > registers. Part of the code/ideas are from
> > https://lore.kernel.org/all/20220419065544.3616948-1-reijiw@google.com .
> > No functional change is intended in this patchset. With the new CPU ID feature
> > registers infrastructure, only writtings of ID_AA64PFR0_EL1.[CSV2|CSV3],
> > ID_AA64DFR0_EL1.PMUVer and ID_DFR0_ELF.PerfMon are allowed as KVM does before.
> >
> > Writable (Configurable) per guest CPU ID feature registers are useful for
> > creating/migrating guest on ARM CPUs with different kinds of features.
> >
> > ---
> >
> > * v4 -> v5
> > - Rebased to 2fad20ae05cb (kvmarm/next)
> > Merge branch kvm-arm64/selftest/misc-6,4 into kvmarm-master/next
>
> Please don't do that. Always use a stable, tagged commit, not some
> random "commit of the day". If there is a dependency, indicate the
> *exact* dependency. Yes, x86 is managed differently.
>
> I'm never going to apply anything on top of an arbitrary commit, so
> this makes it difficult for both you and I. I understand that you want
> to avoid conflicts, but I really don't mind resolving those.
>
> So please stick to existing tags as a base, and describe the
> dependencies you have (in this case, the locking series).
Sure, will do that.
>
> Thanks,
>
> M.
>
> --
> Without deviation from the norm, progress is not possible.
Thanks,
Jing
^ permalink raw reply [flat|nested] 13+ messages in thread
* Re: [PATCH v5 5/6] KVM: arm64: Introduce ID register specific descriptor
2023-04-03 12:27 ` Marc Zyngier
@ 2023-04-03 19:45 ` Jing Zhang
0 siblings, 0 replies; 13+ messages in thread
From: Jing Zhang @ 2023-04-03 19:45 UTC (permalink / raw)
To: Marc Zyngier
Cc: KVM, KVMARM, ARMLinux, Oliver Upton, Will Deacon, Paolo Bonzini,
James Morse, Alexandru Elisei, Suzuki K Poulose, Fuad Tabba,
Reiji Watanabe, Raghavendra Rao Ananta
Hi Marc,
On Mon, Apr 3, 2023 at 5:27 AM Marc Zyngier <maz@kernel.org> wrote:
>
> On Sun, 02 Apr 2023 19:37:34 +0100,
> Jing Zhang <jingzhangos@google.com> wrote:
> >
> > 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@google.com>
> > Signed-off-by: Reiji Watanabe <reijiw@google.com>
> > Signed-off-by: Jing Zhang <jingzhangos@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;
>
> Why do we need to keep this around? we already have all the required
> infrastructure to lookup a full arm64_ftr_reg. So why the added stuff?
You're right. Will use the lookup function.
>
> > + /*
> > + * 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);
>
> Why can't this function return both the required value and a mask?
> Why can't it live in the sys_reg_desc structure?
>
> Frankly, I don't see a good reason to have this wrapper structure
> which makes things pointlessly complicated and prevent code sharing
> with the rest of the infrastructure.
Sure, will reuse the existing fields in sys_reg_desc structure as you
demonstrated.
>
> M.
>
> --
> Without deviation from the norm, progress is not possible.
Thanks,
Jing
^ permalink raw reply [flat|nested] 13+ messages in thread
* Re: [PATCH v5 6/6] KVM: arm64: Refactor writings for PMUVer/CSV2/CSV3
2023-04-03 14:55 ` Marc Zyngier
@ 2023-04-03 19:50 ` Jing Zhang
0 siblings, 0 replies; 13+ messages in thread
From: Jing Zhang @ 2023-04-03 19:50 UTC (permalink / raw)
To: Marc Zyngier
Cc: KVM, KVMARM, ARMLinux, Oliver Upton, Will Deacon, Paolo Bonzini,
James Morse, Alexandru Elisei, Suzuki K Poulose, Fuad Tabba,
Reiji Watanabe, Raghavendra Rao Ananta
Hi Marc,
On Mon, Apr 3, 2023 at 7:55 AM Marc Zyngier <maz@kernel.org> wrote:
>
> On Sun, 02 Apr 2023 19:37:35 +0100,
> Jing Zhang <jingzhangos@google.com> wrote:
> >
> > Refactor writings for ID_AA64PFR0_EL1.[CSV2|CSV3],
> > ID_AA64DFR0_EL1.PMUVer and ID_DFR0_ELF.PerfMon based on utilities
> > introduced by ID register descriptor.
> >
> > No functional change intended.
> >
> > Co-developed-by: Reiji Watanabe <reijiw@google.com>
> > Signed-off-by: Reiji Watanabe <reijiw@google.com>
> > Signed-off-by: Jing Zhang <jingzhangos@google.com>
> > ---
> > arch/arm64/include/asm/cpufeature.h | 5 +
> > arch/arm64/kernel/cpufeature.c | 8 +-
> > arch/arm64/kvm/id_regs.c | 262 +++++++++++++++++++---------
> > arch/arm64/kvm/sys_regs.c | 3 +-
> > arch/arm64/kvm/sys_regs.h | 2 +-
> > 5 files changed, 191 insertions(+), 89 deletions(-)
> >
> > diff --git a/arch/arm64/include/asm/cpufeature.h b/arch/arm64/include/asm/cpufeature.h
> > index 6bf013fb110d..f17e74afe3e9 100644
> > --- a/arch/arm64/include/asm/cpufeature.h
> > +++ b/arch/arm64/include/asm/cpufeature.h
> > @@ -915,6 +915,7 @@ static inline unsigned int get_vmid_bits(u64 mmfr1)
> > return 8;
> > }
> >
> > +s64 arm64_ftr_safe_value(const struct arm64_ftr_bits *ftrp, s64 new, s64 cur);
> > struct arm64_ftr_reg *get_arm64_ftr_reg(u32 sys_id);
> >
> > extern struct arm64_ftr_override id_aa64mmfr1_override;
> > @@ -925,6 +926,10 @@ extern struct arm64_ftr_override id_aa64smfr0_override;
> > extern struct arm64_ftr_override id_aa64isar1_override;
> > extern struct arm64_ftr_override id_aa64isar2_override;
> >
> > +extern const struct arm64_ftr_bits ftr_id_dfr0[];
> > +extern const struct arm64_ftr_bits ftr_id_aa64pfr0[];
> > +extern const struct arm64_ftr_bits ftr_id_aa64dfr0[];
> > +
> > u32 get_kvm_ipa_limit(void);
> > void dump_cpu_features(void);
> >
> > diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
> > index c331c49a7d19..5b0e3379e5f8 100644
> > --- a/arch/arm64/kernel/cpufeature.c
> > +++ b/arch/arm64/kernel/cpufeature.c
> > @@ -225,7 +225,7 @@ static const struct arm64_ftr_bits ftr_id_aa64isar2[] = {
> > ARM64_FTR_END,
> > };
> >
> > -static const struct arm64_ftr_bits ftr_id_aa64pfr0[] = {
> > +const struct arm64_ftr_bits ftr_id_aa64pfr0[] = {
> > ARM64_FTR_BITS(FTR_HIDDEN, FTR_NONSTRICT, FTR_LOWER_SAFE, ID_AA64PFR0_EL1_CSV3_SHIFT, 4, 0),
> > ARM64_FTR_BITS(FTR_HIDDEN, FTR_NONSTRICT, FTR_LOWER_SAFE, ID_AA64PFR0_EL1_CSV2_SHIFT, 4, 0),
> > ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64PFR0_EL1_DIT_SHIFT, 4, 0),
> > @@ -426,7 +426,7 @@ static const struct arm64_ftr_bits ftr_id_mmfr0[] = {
> > ARM64_FTR_END,
> > };
> >
> > -static const struct arm64_ftr_bits ftr_id_aa64dfr0[] = {
> > +const struct arm64_ftr_bits ftr_id_aa64dfr0[] = {
> > S_ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64DFR0_EL1_DoubleLock_SHIFT, 4, 0),
> > ARM64_FTR_BITS(FTR_HIDDEN, FTR_NONSTRICT, FTR_LOWER_SAFE, ID_AA64DFR0_EL1_PMSVer_SHIFT, 4, 0),
> > ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64DFR0_EL1_CTX_CMPs_SHIFT, 4, 0),
> > @@ -578,7 +578,7 @@ static const struct arm64_ftr_bits ftr_id_pfr2[] = {
> > ARM64_FTR_END,
> > };
> >
> > -static const struct arm64_ftr_bits ftr_id_dfr0[] = {
> > +const struct arm64_ftr_bits ftr_id_dfr0[] = {
> > /* [31:28] TraceFilt */
> > S_ARM64_FTR_BITS(FTR_HIDDEN, FTR_NONSTRICT, FTR_EXACT, ID_DFR0_EL1_PerfMon_SHIFT, 4, 0),
> > ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_DFR0_EL1_MProfDbg_SHIFT, 4, 0),
>
> There really isn't a good reason for exposing any of this. You can
> readily get to the overarching arm64_ftr_reg.
Yes, will do.
>
> > @@ -791,7 +791,7 @@ static u64 arm64_ftr_set_value(const struct arm64_ftr_bits *ftrp, s64 reg,
> > return reg;
> > }
> >
> > -static s64 arm64_ftr_safe_value(const struct arm64_ftr_bits *ftrp, s64 new,
> > +s64 arm64_ftr_safe_value(const struct arm64_ftr_bits *ftrp, s64 new,
> > s64 cur)
> > {
> > s64 ret = 0;
> > diff --git a/arch/arm64/kvm/id_regs.c b/arch/arm64/kvm/id_regs.c
> > index af86001e2686..395eaf84a0ab 100644
> > --- a/arch/arm64/kvm/id_regs.c
> > +++ b/arch/arm64/kvm/id_regs.c
> > @@ -39,6 +39,64 @@ struct id_reg_desc {
> > u64 (*read_kvm_sanitised_reg)(const struct id_reg_desc *idr);
> > };
> >
> > +static struct id_reg_desc id_reg_descs[];
> > +
> > +/**
> > + * arm64_check_features() - Check if a feature register value constitutes
> > + * a subset of features indicated by @limit.
> > + *
> > + * @ftrp: Pointer to an array of arm64_ftr_bits. It must be terminated by
> > + * an item whose width field is zero.
> > + * @writable_mask: Indicates writable feature bits.
> > + * @val: The feature register value to check
> > + * @limit: The limit value of the feature register
> > + *
> > + * This function will check if each feature field of @val is the "safe" value
> > + * against @limit based on @ftrp[], each of which specifies the target field
> > + * (shift, width), whether or not the field is for a signed value (sign),
> > + * how the field is determined to be "safe" (type), and the safe value
> > + * (safe_val) when type == FTR_EXACT (safe_val won't be used by this
> > + * function when type != FTR_EXACT). Any other fields in arm64_ftr_bits
> > + * won't be used by this function. If a field value in @val is the same
> > + * as the one in @limit, it is always considered the safe value regardless
> > + * of the type. For register fields that are not in writable, only the value
> > + * in @limit is considered the safe value.
> > + *
> > + * Return: 0 if all the fields are safe. Otherwise, return negative errno.
> > + */
> > +static int arm64_check_features(const struct arm64_ftr_bits *ftrp,
> > + u64 writable_mask, u64 val, u64 limit)
> > +{
> > + u64 mask = 0;
> > +
> > + for (; ftrp && ftrp->width; ftrp++) {
> > + s64 f_val, f_lim, safe_val;
> > + u64 ftr_mask;
> > +
> > + ftr_mask = arm64_ftr_mask(ftrp);
> > + if ((ftr_mask & writable_mask) != ftr_mask)
> > + continue;
> > +
> > + f_val = arm64_ftr_value(ftrp, val);
> > + f_lim = arm64_ftr_value(ftrp, limit);
> > + mask |= ftr_mask;
> > +
> > + if (f_val == f_lim)
> > + safe_val = f_val;
> > + else
> > + safe_val = arm64_ftr_safe_value(ftrp, f_val, f_lim);
> > +
> > + if (safe_val != f_val)
> > + return -E2BIG;
> > + }
> > +
> > + /* For fields that are not writable, values in limit are the safe values. */
> > + if ((val & ~mask) != (limit & ~mask))
> > + return -E2BIG;
> > +
> > + return 0;
> > +}
> > +
> > static u8 vcpu_pmuver(const struct kvm_vcpu *vcpu)
> > {
> > if (kvm_vcpu_has_pmu(vcpu))
> > @@ -84,7 +142,6 @@ u64 kvm_arm_read_id_reg(const struct kvm_vcpu *vcpu, u32 id)
> > case SYS_ID_AA64PFR0_EL1:
> > if (!vcpu_has_sve(vcpu))
> > val &= ~ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_SVE);
> > - val &= ~ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_AMU);
> > if (kvm_vgic_global_state.type == VGIC_V3) {
> > val &= ~ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_GIC);
> > val |= FIELD_PREP(ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_GIC), 1);
> > @@ -111,15 +168,10 @@ u64 kvm_arm_read_id_reg(const struct kvm_vcpu *vcpu, u32 id)
> > val &= ~ARM64_FEATURE_MASK(ID_AA64ISAR2_EL1_WFxT);
> > break;
> > case SYS_ID_AA64DFR0_EL1:
> > - /* Limit debug to ARMv8.0 */
> > - val &= ~ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_DebugVer);
> > - val |= FIELD_PREP(ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_DebugVer), 6);
> > /* Set PMUver to the required version */
> > val &= ~ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_PMUVer);
> > val |= FIELD_PREP(ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_PMUVer),
> > vcpu_pmuver(vcpu));
> > - /* Hide SPE from guests */
> > - val &= ~ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_PMSVer);
> > break;
> > case SYS_ID_DFR0_EL1:
> > val &= ~ARM64_FEATURE_MASK(ID_DFR0_EL1_PerfMon);
> > @@ -178,9 +230,16 @@ static int get_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,
> > u64 val)
> > {
> > - /* This is what we mean by invariant: you can't change it. */
> > - if (val != read_id_reg(vcpu, rd))
> > - return -EINVAL;
> > + int ret;
> > + int id = reg_to_encoding(rd);
> > + const struct id_reg_desc *idr = &id_reg_descs[IDREG_IDX(id)];
> > +
> > + ret = arm64_check_features(idr->ftr_bits, idr->writable_mask, val,
> > + idr->read_kvm_sanitised_reg ? idr->read_kvm_sanitised_reg(idr) : 0);
> > + if (ret)
> > + return ret;
> > +
> > + IDREG(vcpu->kvm, id) = val;
> >
> > return 0;
> > }
> > @@ -219,12 +278,39 @@ 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 u64 read_sanitised_id_aa64pfr0_el1(const struct id_reg_desc *idr)
> > +{
> > + u64 val;
> > + u32 id = reg_to_encoding(&idr->reg_desc);
> > +
> > + val = read_sanitised_ftr_reg(id);
> > + /*
> > + * The default is to expose CSV2 == 1 if the HW isn't affected.
> > + * Although this is a per-CPU feature, we make it global because
> > + * asymmetric systems are just a nuisance.
> > + *
> > + * Userspace can override this as long as it doesn't promise
> > + * the impossible.
> > + */
> > + if (arm64_get_spectre_v2_state() == SPECTRE_UNAFFECTED) {
> > + val &= ~ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_CSV2);
> > + val |= FIELD_PREP(ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_CSV2), 1);
> > + }
> > + if (arm64_get_meltdown_state() == SPECTRE_UNAFFECTED) {
> > + val &= ~ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_CSV3);
> > + val |= FIELD_PREP(ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_CSV3), 1);
> > + }
> > +
> > + val &= ~ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_AMU);
> > +
> > + return val;
> > +}
> > +
> > static int set_id_aa64pfr0_el1(struct kvm_vcpu *vcpu,
> > const struct sys_reg_desc *rd,
> > u64 val)
> > {
> > u8 csv2, csv3;
> > - u64 sval = val;
> >
> > /*
> > * Allow AA64PFR0_EL1.CSV2 to be set from userspace as long as
> > @@ -232,26 +318,37 @@ static int set_id_aa64pfr0_el1(struct kvm_vcpu *vcpu,
> > * guest could otherwise be covered in ectoplasmic residue).
> > */
> > csv2 = cpuid_feature_extract_unsigned_field(val, ID_AA64PFR0_EL1_CSV2_SHIFT);
> > - if (csv2 > 1 ||
> > - (csv2 && arm64_get_spectre_v2_state() != SPECTRE_UNAFFECTED))
> > + if (csv2 > 1 || (csv2 && arm64_get_spectre_v2_state() != SPECTRE_UNAFFECTED))
> > return -EINVAL;
> >
> > /* Same thing for CSV3 */
> > csv3 = cpuid_feature_extract_unsigned_field(val, ID_AA64PFR0_EL1_CSV3_SHIFT);
> > - if (csv3 > 1 ||
> > - (csv3 && arm64_get_meltdown_state() != SPECTRE_UNAFFECTED))
> > + if (csv3 > 1 || (csv3 && arm64_get_meltdown_state() != SPECTRE_UNAFFECTED))
> > return -EINVAL;
> >
> > - /* We can only differ with CSV[23], and anything else is an error */
> > - val ^= read_id_reg(vcpu, rd);
> > - val &= ~(ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_CSV2) |
> > - ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_CSV3));
> > - if (val)
> > - return -EINVAL;
> > + return set_id_reg(vcpu, rd, val);
> > +}
> >
> > - IDREG(vcpu->kvm, reg_to_encoding(rd)) = sval;
> > +static u64 read_sanitised_id_aa64dfr0_el1(const struct id_reg_desc *idr)
> > +{
> > + u64 val;
> > + u32 id = reg_to_encoding(&idr->reg_desc);
> >
> > - return 0;
> > + val = read_sanitised_ftr_reg(id);
> > + /* Limit debug to ARMv8.0 */
> > + val &= ~ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_DebugVer);
> > + val |= FIELD_PREP(ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_DebugVer), 6);
> > + /*
> > + * Initialise the default PMUver before there is a chance to
> > + * create an actual PMU.
> > + */
> > + val &= ~ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_PMUVer);
> > + val |= FIELD_PREP(ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_PMUVer),
> > + kvm_arm_pmu_get_pmuver_limit());
> > + /* Hide SPE from guests */
> > + val &= ~ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_PMSVer);
> > +
> > + return val;
> > }
> >
> > static int set_id_aa64dfr0_el1(struct kvm_vcpu *vcpu,
> > @@ -260,6 +357,7 @@ static int set_id_aa64dfr0_el1(struct kvm_vcpu *vcpu,
> > {
> > u8 pmuver, host_pmuver;
> > bool valid_pmu;
> > + int ret;
> >
> > host_pmuver = kvm_arm_pmu_get_pmuver_limit();
> >
> > @@ -279,23 +377,25 @@ static int set_id_aa64dfr0_el1(struct kvm_vcpu *vcpu,
> > if (kvm_vcpu_has_pmu(vcpu) != valid_pmu)
> > return -EINVAL;
> >
> > - /* We can only differ with PMUver, and anything else is an error */
> > - val ^= read_id_reg(vcpu, rd);
> > - val &= ~ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_PMUVer);
> > - if (val)
> > - return -EINVAL;
> > -
> > if (valid_pmu) {
> > mutex_lock(&vcpu->kvm->arch.config_lock);
> > - IDREG(vcpu->kvm, SYS_ID_AA64DFR0_EL1) &= ~ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_PMUVer);
> > - IDREG(vcpu->kvm, SYS_ID_AA64DFR0_EL1) |=
> > - FIELD_PREP(ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_PMUVer), pmuver);
> > + ret = set_id_reg(vcpu, rd, val);
> > + if (ret) {
> > + mutex_unlock(&vcpu->kvm->arch.config_lock);
> > + return ret;
> > + }
> >
> > IDREG(vcpu->kvm, SYS_ID_DFR0_EL1) &= ~ARM64_FEATURE_MASK(ID_DFR0_EL1_PerfMon);
> > IDREG(vcpu->kvm, SYS_ID_DFR0_EL1) |=
> > FIELD_PREP(ARM64_FEATURE_MASK(ID_DFR0_EL1_PerfMon), pmuver_to_perfmon(pmuver));
>
> I repeatedly asked for assignments to be *on a single line*.
Will fix it.
>
> > mutex_unlock(&vcpu->kvm->arch.config_lock);
> > } else {
> > + /* We can only differ with PMUver, and anything else is an error */
> > + val ^= read_id_reg(vcpu, rd);
> > + val &= ~ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_PMUVer);
> > + if (val)
> > + return -EINVAL;
> > +
>
> I asked about this before. Why do we need this? Isn't the whole point
> of the exercise to have a *unified* way to check for the writable
> bits? If you still need to open-code that, the whole exercise is a
> bit pointless, isn't it?
Right. Will find a better way.
>
> Frankly, the whole thing is going the wrong way, starting with the
> wrapping data structure. We already have most of what we need in
> sys_reg_desc, and it only takes a bit of imagination to get there.
>
> I've spent a couple of hours hacking away at the series, and got rid
> of it entirely, simply by repurposing exist fields (val for the write
> mask, reset for the limit value). All I can say is that it compiles.
>
> But at least it doesn't reinvent the wheel.
>
> M.
>
> diff --git a/arch/arm64/kvm/id_regs.c b/arch/arm64/kvm/id_regs.c
> index 395eaf84a0ab..30f36e0dd12e 100644
> --- a/arch/arm64/kvm/id_regs.c
> +++ b/arch/arm64/kvm/id_regs.c
> @@ -18,29 +18,6 @@
>
> #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 struct id_reg_desc id_reg_descs[];
> -
> /**
> * arm64_check_features() - Check if a feature register value constitutes
> * a subset of features indicated by @limit.
> @@ -64,11 +41,26 @@ static struct id_reg_desc id_reg_descs[];
> *
> * Return: 0 if all the fields are safe. Otherwise, return negative errno.
> */
> -static int arm64_check_features(const struct arm64_ftr_bits *ftrp,
> - u64 writable_mask, u64 val, u64 limit)
> +static int arm64_check_features(struct kvm_vcpu *vcpu,
> + const struct sys_reg_desc *rd,
> + u64 val)
> {
> + const struct arm64_ftr_reg *ftr_reg;
> + const struct arm64_ftr_bits *ftrp;
> + u32 id = reg_to_encoding(rd);
> + u64 writable_mask = rd->val;
> + u64 limit = 0;
> u64 mask = 0;
>
> + if (rd->reset)
> + limit = rd->reset(vcpu, rd);
> +
> + ftr_reg = get_arm64_ftr_reg(id);
> + if (!ftr_reg)
> + return -EINVAL;
> +
> + ftrp = ftr_reg->ftr_bits;
> +
> for (; ftrp && ftrp->width; ftrp++) {
> s64 f_val, f_lim, safe_val;
> u64 ftr_mask;
> @@ -230,12 +222,10 @@ static int get_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,
> u64 val)
> {
> + u32 id = reg_to_encoding(rd);
> int ret;
> - int id = reg_to_encoding(rd);
> - const struct id_reg_desc *idr = &id_reg_descs[IDREG_IDX(id)];
>
> - ret = arm64_check_features(idr->ftr_bits, idr->writable_mask, val,
> - idr->read_kvm_sanitised_reg ? idr->read_kvm_sanitised_reg(idr) : 0);
> + ret = arm64_check_features(vcpu, rd, val);
> if (ret)
> return ret;
>
> @@ -273,15 +263,17 @@ 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)
> +static u64 general_read_kvm_sanitised_reg(struct kvm_vcpu *vcpu,
> + const struct sys_reg_desc *r)
> {
> - return read_sanitised_ftr_reg(reg_to_encoding(&idr->reg_desc));
> + return read_sanitised_ftr_reg(reg_to_encoding(r));
> }
>
> -static u64 read_sanitised_id_aa64pfr0_el1(const struct id_reg_desc *idr)
> +static u64 read_sanitised_id_aa64pfr0_el1(struct kvm_vcpu *vcpu,
> + const struct sys_reg_desc *r)
> {
> u64 val;
> - u32 id = reg_to_encoding(&idr->reg_desc);
> + u32 id = reg_to_encoding(r);
>
> val = read_sanitised_ftr_reg(id);
> /*
> @@ -329,10 +321,11 @@ static int set_id_aa64pfr0_el1(struct kvm_vcpu *vcpu,
> return set_id_reg(vcpu, rd, val);
> }
>
> -static u64 read_sanitised_id_aa64dfr0_el1(const struct id_reg_desc *idr)
> +static u64 read_sanitised_id_aa64dfr0_el1(struct kvm_vcpu *vcpu,
> + const struct sys_reg_desc *r)
> {
> u64 val;
> - u32 id = reg_to_encoding(&idr->reg_desc);
> + u32 id = reg_to_encoding(r);
>
> val = read_sanitised_ftr_reg(id);
> /* Limit debug to ARMv8.0 */
> @@ -403,10 +396,11 @@ static int set_id_aa64dfr0_el1(struct kvm_vcpu *vcpu,
> return 0;
> }
>
> -static u64 read_sanitised_id_dfr0_el1(const struct id_reg_desc *idr)
> +static u64 read_sanitised_id_dfr0_el1(struct kvm_vcpu *vcpu,
> + const struct sys_reg_desc *r)
> {
> u64 val;
> - u32 id = reg_to_encoding(&idr->reg_desc);
> + u32 id = reg_to_encoding(r);
>
> val = read_sanitised_ftr_reg(id);
> /*
> @@ -473,33 +467,23 @@ static int set_id_dfr0_el1(struct kvm_vcpu *vcpu,
> }
>
> /* sys_reg_desc initialiser for known cpufeature ID registers */
> -#define SYS_DESC_SANITISED(name) { \
> +#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_SANITISED(name), \
> - .ftr_bits = NULL, \
> - .writable_mask = 0, \
> - .read_kvm_sanitised_reg = general_read_kvm_sanitised_reg, \
> + .reset = general_read_kvm_sanitised_reg, \
> }
>
> /* sys_reg_desc initialiser for known cpufeature ID registers */
> -#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, \
> +#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, \
> + .reset = general_read_kvm_sanitised_reg, \
> }
>
> /*
> @@ -508,16 +492,11 @@ static int set_id_dfr0_el1(struct kvm_vcpu *vcpu,
> * (1 <= crm < 8, 0 <= Op2 < 8).
> */
> #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, \
> }
>
> /*
> @@ -526,19 +505,14 @@ static int set_id_dfr0_el1(struct kvm_vcpu *vcpu,
> * RAZ for the guest.
> */
> #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 struct id_reg_desc id_reg_descs[KVM_ARM_ID_REG_NUM] = {
> +static struct sys_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[].
> @@ -548,15 +522,14 @@ static struct id_reg_desc id_reg_descs[KVM_ARM_ID_REG_NUM] = {
> /* CRm=1 */
> AA32_ID_SANITISED(ID_PFR0_EL1),
> AA32_ID_SANITISED(ID_PFR1_EL1),
> - { .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, },
> - .ftr_bits = ftr_id_dfr0,
> - .writable_mask = ID_DFR0_EL1_PerfMon_MASK,
> - .read_kvm_sanitised_reg = read_sanitised_id_dfr0_el1,
> + .visibility = aa32_id_visibility,
> + .val = ID_DFR0_EL1_PerfMon_MASK,
> + .reset = read_sanitised_id_dfr0_el1,
> },
> ID_HIDDEN(ID_AFR0_EL1),
> AA32_ID_SANITISED(ID_MMFR0_EL1),
> @@ -586,14 +559,13 @@ static struct id_reg_desc id_reg_descs[KVM_ARM_ID_REG_NUM] = {
>
> /* AArch64 ID registers */
> /* CRm=4 */
> - { .reg_desc = {
> + {
> SYS_DESC(SYS_ID_AA64PFR0_EL1),
> .access = access_id_reg,
> .get_user = get_id_reg,
> - .set_user = set_id_aa64pfr0_el1, },
> - .ftr_bits = ftr_id_aa64pfr0,
> - .writable_mask = ID_AA64PFR0_EL1_CSV2_MASK | ID_AA64PFR0_EL1_CSV3_MASK,
> - .read_kvm_sanitised_reg = read_sanitised_id_aa64pfr0_el1,
> + .set_user = set_id_aa64pfr0_el1,
> + .val = ID_AA64PFR0_EL1_CSV2_MASK | ID_AA64PFR0_EL1_CSV3_MASK,
> + .reset = read_sanitised_id_aa64pfr0_el1,
> },
> ID_SANITISED(ID_AA64PFR1_EL1),
> ID_UNALLOCATED(4, 2),
> @@ -604,14 +576,13 @@ static struct id_reg_desc id_reg_descs[KVM_ARM_ID_REG_NUM] = {
> ID_UNALLOCATED(4, 7),
>
> /* CRm=5 */
> - { .reg_desc = {
> + {
> SYS_DESC(SYS_ID_AA64DFR0_EL1),
> .access = access_id_reg,
> .get_user = get_id_reg,
> - .set_user = set_id_aa64dfr0_el1, },
> - .ftr_bits = ftr_id_aa64dfr0,
> - .writable_mask = ID_AA64DFR0_EL1_PMUVer_MASK,
> - .read_kvm_sanitised_reg = read_sanitised_id_aa64dfr0_el1,
> + .set_user = set_id_aa64dfr0_el1,
> + .val = ID_AA64DFR0_EL1_PMUVer_MASK,
> + .reset = read_sanitised_id_aa64dfr0_el1,
> },
> ID_SANITISED(ID_AA64DFR1_EL1),
> ID_UNALLOCATED(5, 2),
> @@ -648,7 +619,7 @@ static const struct sys_reg_desc *id_params_to_desc(struct sys_reg_params *param
>
> id = reg_to_encoding(params);
> if (is_id_reg(id))
> - return &id_reg_descs[IDREG_IDX(id)].reg_desc;
> + return &id_reg_descs[IDREG_IDX(id)];
>
> return NULL;
> }
> @@ -742,11 +713,11 @@ bool kvm_arm_idreg_table_init(void)
> 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;
> + const struct sys_reg_desc *r = &id_reg_descs[i];
>
> 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);
> + id_reg_descs, i);
> return false;
> }
> }
> @@ -756,7 +727,7 @@ bool kvm_arm_idreg_table_init(void)
>
> int kvm_arm_walk_id_regs(struct kvm_vcpu *vcpu, u64 __user *uind)
> {
> - const struct id_reg_desc *i2, *end2;
> + const struct sys_reg_desc *i2, *end2;
> unsigned int total = 0;
> int err;
>
> @@ -764,7 +735,7 @@ int kvm_arm_walk_id_regs(struct kvm_vcpu *vcpu, u64 __user *uind)
> end2 = id_reg_descs + ARRAY_SIZE(id_reg_descs);
>
> for (; i2 != end2; i2++) {
> - err = walk_one_sys_reg(vcpu, &(i2->reg_desc), &uind, &total);
> + err = walk_one_sys_reg(vcpu, i2, &uind, &total);
> if (err)
> return err;
> }
> @@ -779,11 +750,11 @@ 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].reg_desc);
> + id = reg_to_encoding(&id_reg_descs[i]);
>
> val = 0;
> - if (id_reg_descs[i].read_kvm_sanitised_reg)
> - val = id_reg_descs[i].read_kvm_sanitised_reg(&id_reg_descs[i]);
> + if (id_reg_descs[i].reset)
> + val = id_reg_descs[i].reset(NULL, &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 b90d1d3ad081..c4f498e75315 100644
> --- a/arch/arm64/kvm/sys_regs.c
> +++ b/arch/arm64/kvm/sys_regs.c
> @@ -540,10 +540,11 @@ static int get_bvr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
> return 0;
> }
>
> -static void reset_bvr(struct kvm_vcpu *vcpu,
> +static u64 reset_bvr(struct kvm_vcpu *vcpu,
> const struct sys_reg_desc *rd)
> {
> vcpu->arch.vcpu_debug_state.dbg_bvr[rd->CRm] = rd->val;
> + return rd->val;
> }
>
> static bool trap_bcr(struct kvm_vcpu *vcpu,
> @@ -576,10 +577,11 @@ static int get_bcr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
> return 0;
> }
>
> -static void reset_bcr(struct kvm_vcpu *vcpu,
> +static u64 reset_bcr(struct kvm_vcpu *vcpu,
> const struct sys_reg_desc *rd)
> {
> vcpu->arch.vcpu_debug_state.dbg_bcr[rd->CRm] = rd->val;
> + return rd->val;
> }
>
> static bool trap_wvr(struct kvm_vcpu *vcpu,
> @@ -613,10 +615,11 @@ static int get_wvr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
> return 0;
> }
>
> -static void reset_wvr(struct kvm_vcpu *vcpu,
> +static u64 reset_wvr(struct kvm_vcpu *vcpu,
> const struct sys_reg_desc *rd)
> {
> vcpu->arch.vcpu_debug_state.dbg_wvr[rd->CRm] = rd->val;
> + return rd->val;
> }
>
> static bool trap_wcr(struct kvm_vcpu *vcpu,
> @@ -649,25 +652,28 @@ static int get_wcr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
> return 0;
> }
>
> -static void reset_wcr(struct kvm_vcpu *vcpu,
> +static u64 reset_wcr(struct kvm_vcpu *vcpu,
> const struct sys_reg_desc *rd)
> {
> vcpu->arch.vcpu_debug_state.dbg_wcr[rd->CRm] = rd->val;
> + return rd->val;
> }
>
> -static void reset_amair_el1(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
> +static u64 reset_amair_el1(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
> {
> u64 amair = read_sysreg(amair_el1);
> vcpu_write_sys_reg(vcpu, amair, AMAIR_EL1);
> + return amair;
> }
>
> -static void reset_actlr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
> +static u64 reset_actlr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
> {
> u64 actlr = read_sysreg(actlr_el1);
> vcpu_write_sys_reg(vcpu, actlr, ACTLR_EL1);
> + return actlr;
> }
>
> -static void reset_mpidr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
> +static u64 reset_mpidr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
> {
> u64 mpidr;
>
> @@ -681,7 +687,9 @@ static void reset_mpidr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
> mpidr = (vcpu->vcpu_id & 0x0f) << MPIDR_LEVEL_SHIFT(0);
> mpidr |= ((vcpu->vcpu_id >> 4) & 0xff) << MPIDR_LEVEL_SHIFT(1);
> mpidr |= ((vcpu->vcpu_id >> 12) & 0xff) << MPIDR_LEVEL_SHIFT(2);
> - vcpu_write_sys_reg(vcpu, (1ULL << 31) | mpidr, MPIDR_EL1);
> + mpidr |= (1ULL << 31);
> + vcpu_write_sys_reg(vcpu, mpidr, MPIDR_EL1);
> + return mpidr;
> }
>
> static unsigned int pmu_visibility(const struct kvm_vcpu *vcpu,
> @@ -693,13 +701,13 @@ static unsigned int pmu_visibility(const struct kvm_vcpu *vcpu,
> return REG_HIDDEN;
> }
>
> -static void reset_pmu_reg(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
> +static u64 reset_pmu_reg(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
> {
> u64 n, mask = BIT(ARMV8_PMU_CYCLE_IDX);
>
> /* No PMU available, any PMU reg may UNDEF... */
> if (!kvm_arm_support_pmu_v3())
> - return;
> + return 0;
>
> n = read_sysreg(pmcr_el0) >> ARMV8_PMU_PMCR_N_SHIFT;
> n &= ARMV8_PMU_PMCR_N_MASK;
> @@ -708,33 +716,37 @@ static void reset_pmu_reg(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
>
> reset_unknown(vcpu, r);
> __vcpu_sys_reg(vcpu, r->reg) &= mask;
> + return __vcpu_sys_reg(vcpu, r->reg);
> }
>
> -static void reset_pmevcntr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
> +static u64 reset_pmevcntr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
> {
> reset_unknown(vcpu, r);
> __vcpu_sys_reg(vcpu, r->reg) &= GENMASK(31, 0);
> + return __vcpu_sys_reg(vcpu, r->reg);
> }
>
> -static void reset_pmevtyper(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
> +static u64 reset_pmevtyper(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
> {
> reset_unknown(vcpu, r);
> __vcpu_sys_reg(vcpu, r->reg) &= ARMV8_PMU_EVTYPE_MASK;
> + return __vcpu_sys_reg(vcpu, r->reg);
> }
>
> -static void reset_pmselr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
> +static u64 reset_pmselr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
> {
> reset_unknown(vcpu, r);
> __vcpu_sys_reg(vcpu, r->reg) &= ARMV8_PMU_COUNTER_MASK;
> + return __vcpu_sys_reg(vcpu, r->reg);
> }
>
> -static void reset_pmcr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
> +static u64 reset_pmcr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
> {
> u64 pmcr;
>
> /* No PMU available, PMCR_EL0 may UNDEF... */
> if (!kvm_arm_support_pmu_v3())
> - return;
> + return 0;
>
> /* Only preserve PMCR_EL0.N, and reset the rest to 0 */
> pmcr = read_sysreg(pmcr_el0) & (ARMV8_PMU_PMCR_N_MASK << ARMV8_PMU_PMCR_N_SHIFT);
> @@ -742,6 +754,7 @@ static void reset_pmcr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
> pmcr |= ARMV8_PMU_PMCR_LC;
>
> __vcpu_sys_reg(vcpu, r->reg) = pmcr;
> + return __vcpu_sys_reg(vcpu, r->reg);
> }
>
> static bool check_pmu_access_disabled(struct kvm_vcpu *vcpu, u64 flags)
> @@ -1205,7 +1218,7 @@ static bool access_clidr(struct kvm_vcpu *vcpu, struct sys_reg_params *p,
> * Fabricate a CLIDR_EL1 value instead of using the real value, which can vary
> * by the physical CPU which the vcpu currently resides in.
> */
> -static void reset_clidr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
> +static u64 reset_clidr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
> {
> u64 ctr_el0 = read_sanitised_ftr_reg(SYS_CTR_EL0);
> u64 clidr;
> @@ -1253,6 +1266,7 @@ static void reset_clidr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
> clidr |= 2 << CLIDR_TTYPE_SHIFT(loc);
>
> __vcpu_sys_reg(vcpu, r->reg) = clidr;
> + return __vcpu_sys_reg(vcpu, r->reg);
> }
>
> static int set_clidr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
> @@ -2603,19 +2617,21 @@ id_to_sys_reg_desc(struct kvm_vcpu *vcpu, u64 id,
> */
>
> #define FUNCTION_INVARIANT(reg) \
> - static void get_##reg(struct kvm_vcpu *v, \
> + static u64 get_##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(midr_el1)
> FUNCTION_INVARIANT(revidr_el1)
> FUNCTION_INVARIANT(aidr_el1)
>
> -static void get_ctr_el0(struct kvm_vcpu *v, const struct sys_reg_desc *r)
> +static u64 get_ctr_el0(struct kvm_vcpu *v, const struct sys_reg_desc *r)
> {
> ((struct sys_reg_desc *)r)->val = read_sanitised_ftr_reg(SYS_CTR_EL0);
> + return ((struct sys_reg_desc *)r)->val;
> }
>
> /* ->val is filled in by kvm_sys_reg_table_init() */
> diff --git a/arch/arm64/kvm/sys_regs.h b/arch/arm64/kvm/sys_regs.h
> index df8d26df93ec..d14d5b41a222 100644
> --- a/arch/arm64/kvm/sys_regs.h
> +++ b/arch/arm64/kvm/sys_regs.h
> @@ -65,12 +65,12 @@ struct sys_reg_desc {
> const struct sys_reg_desc *);
>
> /* Initialization for vcpu. */
> - void (*reset)(struct kvm_vcpu *, const struct sys_reg_desc *);
> + u64 (*reset)(struct kvm_vcpu *, const struct sys_reg_desc *);
>
> /* Index into sys_reg[], or 0 if we don't need to save it. */
> int reg;
>
> - /* Value (usually reset value) */
> + /* Value (usually reset value), or write mask for idregs */
> u64 val;
>
> /* Custom get/set_user functions, fallback to generic if NULL */
> @@ -123,19 +123,21 @@ static inline bool read_zero(struct kvm_vcpu *vcpu,
> }
>
> /* Reset functions */
> -static inline void reset_unknown(struct kvm_vcpu *vcpu,
> +static inline u64 reset_unknown(struct kvm_vcpu *vcpu,
> const struct sys_reg_desc *r)
> {
> BUG_ON(!r->reg);
> BUG_ON(r->reg >= NR_SYS_REGS);
> __vcpu_sys_reg(vcpu, r->reg) = 0x1de7ec7edbadc0deULL;
> + return __vcpu_sys_reg(vcpu, r->reg);
> }
>
> -static inline void reset_val(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
> +static inline u64 reset_val(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
> {
> BUG_ON(!r->reg);
> BUG_ON(r->reg >= NR_SYS_REGS);
> __vcpu_sys_reg(vcpu, r->reg) = r->val;
> + return __vcpu_sys_reg(vcpu, r->reg);
> }
>
> static inline unsigned int sysreg_visibility(const struct kvm_vcpu *vcpu,
Really appreciate it. It looks great! Will reimplement based on your suggestion.
>
> --
> Without deviation from the norm, progress is not possible.
Thanks,
Jing
^ permalink raw reply [flat|nested] 13+ messages in thread
end of thread, other threads:[~2023-04-03 19:50 UTC | newest]
Thread overview: 13+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2023-04-02 18:37 [PATCH v5 0/6] Support writable CPU ID registers from userspace Jing Zhang
2023-04-02 18:37 ` [PATCH v5 1/6] KVM: arm64: Move CPU ID feature registers emulation into a separate file Jing Zhang
2023-04-02 18:37 ` [PATCH v5 2/6] KVM: arm64: Save ID registers' sanitized value per guest Jing Zhang
2023-04-02 18:37 ` [PATCH v5 3/6] KVM: arm64: Use per guest ID register for ID_AA64PFR0_EL1.[CSV2|CSV3] Jing Zhang
2023-04-02 18:37 ` [PATCH v5 4/6] KVM: arm64: Use per guest ID register for ID_AA64DFR0_EL1.PMUVer Jing Zhang
2023-04-02 18:37 ` [PATCH v5 5/6] KVM: arm64: Introduce ID register specific descriptor Jing Zhang
2023-04-03 12:27 ` Marc Zyngier
2023-04-03 19:45 ` Jing Zhang
2023-04-02 18:37 ` [PATCH v5 6/6] KVM: arm64: Refactor writings for PMUVer/CSV2/CSV3 Jing Zhang
2023-04-03 14:55 ` Marc Zyngier
2023-04-03 19:50 ` Jing Zhang
2023-04-03 10:30 ` [PATCH v5 0/6] Support writable CPU ID registers from userspace Marc Zyngier
2023-04-03 19:42 ` Jing Zhang
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