[PATCH v1 02/12] KVM: arm64: Group setting traps for protected VMs by control register
Fuad Tabba
tabba at google.com
Wed Nov 20 02:52:44 PST 2024
Group setting protected vm traps by control register rather than
feature id register, since some trap values (e.g., PAuth), depend
on more than one feature id register.
Signed-off-by: Fuad Tabba <tabba at google.com>
---
arch/arm64/kvm/hyp/nvhe/pkvm.c | 317 +++++++++++++++------------------
1 file changed, 144 insertions(+), 173 deletions(-)
diff --git a/arch/arm64/kvm/hyp/nvhe/pkvm.c b/arch/arm64/kvm/hyp/nvhe/pkvm.c
index 76a70fee7647..1744574e79b2 100644
--- a/arch/arm64/kvm/hyp/nvhe/pkvm.c
+++ b/arch/arm64/kvm/hyp/nvhe/pkvm.c
@@ -23,233 +23,204 @@ unsigned int kvm_arm_vmid_bits;
unsigned int kvm_host_sve_max_vl;
-/*
- * Set trap register values based on features in ID_AA64PFR0.
- */
-static void pvm_init_traps_aa64pfr0(struct kvm_vcpu *vcpu)
+static void pkvm_vcpu_reset_hcr(struct kvm_vcpu *vcpu)
{
- const u64 feature_ids = pvm_read_id_reg(vcpu, SYS_ID_AA64PFR0_EL1);
- u64 hcr_set = HCR_RW;
- u64 hcr_clear = 0;
- u64 cptr_set = 0;
- u64 cptr_clear = 0;
-
- /* Protected KVM does not support AArch32 guests. */
- BUILD_BUG_ON(FIELD_GET(ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_EL0),
- PVM_ID_AA64PFR0_ALLOW) != ID_AA64PFR0_EL1_EL0_IMP);
- BUILD_BUG_ON(FIELD_GET(ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_EL1),
- PVM_ID_AA64PFR0_ALLOW) != ID_AA64PFR0_EL1_EL1_IMP);
-
- /*
- * Linux guests assume support for floating-point and Advanced SIMD. Do
- * not change the trapping behavior for these from the KVM default.
- */
- BUILD_BUG_ON(!FIELD_GET(ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_FP),
- PVM_ID_AA64PFR0_ALLOW));
- BUILD_BUG_ON(!FIELD_GET(ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_AdvSIMD),
- PVM_ID_AA64PFR0_ALLOW));
+ vcpu->arch.hcr_el2 = HCR_GUEST_FLAGS;
if (has_hvhe())
- hcr_set |= HCR_E2H;
+ vcpu->arch.hcr_el2 |= HCR_E2H;
- /* Trap RAS unless all current versions are supported */
- if (FIELD_GET(ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_RAS), feature_ids) <
- ID_AA64PFR0_EL1_RAS_V1P1) {
- hcr_set |= HCR_TERR | HCR_TEA;
- hcr_clear |= HCR_FIEN;
+ if (cpus_have_final_cap(ARM64_HAS_RAS_EXTN)) {
+ /* route synchronous external abort exceptions to EL2 */
+ vcpu->arch.hcr_el2 |= HCR_TEA;
+ /* trap error record accesses */
+ vcpu->arch.hcr_el2 |= HCR_TERR;
}
- /* Trap AMU */
- if (!FIELD_GET(ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_AMU), feature_ids)) {
- hcr_clear |= HCR_AMVOFFEN;
- cptr_set |= CPTR_EL2_TAM;
- }
+ if (cpus_have_final_cap(ARM64_HAS_STAGE2_FWB))
+ vcpu->arch.hcr_el2 |= HCR_FWB;
- /* Trap SVE */
- if (!FIELD_GET(ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_SVE), feature_ids)) {
- if (has_hvhe())
- cptr_clear |= CPACR_ELx_ZEN;
- else
- cptr_set |= CPTR_EL2_TZ;
- }
+ if (cpus_have_final_cap(ARM64_HAS_EVT) &&
+ !cpus_have_final_cap(ARM64_MISMATCHED_CACHE_TYPE))
+ vcpu->arch.hcr_el2 |= HCR_TID4;
+ else
+ vcpu->arch.hcr_el2 |= HCR_TID2;
- vcpu->arch.hcr_el2 |= hcr_set;
- vcpu->arch.hcr_el2 &= ~hcr_clear;
- vcpu->arch.cptr_el2 |= cptr_set;
- vcpu->arch.cptr_el2 &= ~cptr_clear;
+ if (vcpu_has_ptrauth(vcpu))
+ vcpu->arch.hcr_el2 |= (HCR_API | HCR_APK);
}
-/*
- * Set trap register values based on features in ID_AA64PFR1.
- */
-static void pvm_init_traps_aa64pfr1(struct kvm_vcpu *vcpu)
+static void pvm_init_traps_hcr(struct kvm_vcpu *vcpu)
{
- const u64 feature_ids = pvm_read_id_reg(vcpu, SYS_ID_AA64PFR1_EL1);
- u64 hcr_set = 0;
- u64 hcr_clear = 0;
+ const u64 id_aa64pfr0 = pvm_read_id_reg(vcpu, SYS_ID_AA64PFR0_EL1);
+ const u64 id_aa64pfr1 = pvm_read_id_reg(vcpu, SYS_ID_AA64PFR1_EL1);
+ const u64 id_aa64mmfr1 = pvm_read_id_reg(vcpu, SYS_ID_AA64MMFR1_EL1);
+ u64 val = vcpu->arch.hcr_el2;
+
+ /* No support for AArch32. */
+ val |= HCR_RW;
+
+ if (has_hvhe())
+ val |= HCR_E2H;
+
+ /*
+ * Always trap:
+ * - Feature id registers: to control features exposed to guests
+ * - Implementation-defined features
+ */
+ val |= HCR_TACR | HCR_TIDCP | HCR_TID3 | HCR_TID1;
+
+ /* Trap RAS unless all current versions are supported */
+ if (FIELD_GET(ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_RAS), id_aa64pfr0) <
+ ID_AA64PFR0_EL1_RAS_V1P1) {
+ val |= HCR_TERR | HCR_TEA;
+ val &= ~(HCR_FIEN);
+ }
+
+ /* Trap AMU */
+ if (!FIELD_GET(ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_AMU), id_aa64pfr0))
+ val &= ~(HCR_AMVOFFEN);
/* Memory Tagging: Trap and Treat as Untagged if not supported. */
- if (!FIELD_GET(ARM64_FEATURE_MASK(ID_AA64PFR1_EL1_MTE), feature_ids)) {
- hcr_set |= HCR_TID5;
- hcr_clear |= HCR_DCT | HCR_ATA;
+ if (!FIELD_GET(ARM64_FEATURE_MASK(ID_AA64PFR1_EL1_MTE), id_aa64pfr1)) {
+ val |= HCR_TID5;
+ val &= ~(HCR_DCT | HCR_ATA);
}
- vcpu->arch.hcr_el2 |= hcr_set;
- vcpu->arch.hcr_el2 &= ~hcr_clear;
+ /* Trap LOR */
+ if (!FIELD_GET(ARM64_FEATURE_MASK(ID_AA64MMFR1_EL1_LO), id_aa64mmfr1))
+ val |= HCR_TLOR;
+
+ vcpu->arch.hcr_el2 = val;
}
-/*
- * Set trap register values based on features in ID_AA64DFR0.
- */
-static void pvm_init_traps_aa64dfr0(struct kvm_vcpu *vcpu)
+static void pvm_init_traps_cptr(struct kvm_vcpu *vcpu)
{
- const u64 feature_ids = pvm_read_id_reg(vcpu, SYS_ID_AA64DFR0_EL1);
- u64 mdcr_set = 0;
- u64 mdcr_clear = 0;
- u64 cptr_set = 0;
+ const u64 id_aa64pfr0 = pvm_read_id_reg(vcpu, SYS_ID_AA64PFR0_EL1);
+ const u64 id_aa64pfr1 = pvm_read_id_reg(vcpu, SYS_ID_AA64PFR1_EL1);
+ const u64 id_aa64dfr0 = pvm_read_id_reg(vcpu, SYS_ID_AA64DFR0_EL1);
+ u64 val = vcpu->arch.cptr_el2;
- /* Trap/constrain PMU */
- if (!FIELD_GET(ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_PMUVer), feature_ids)) {
- mdcr_set |= MDCR_EL2_TPM | MDCR_EL2_TPMCR;
- mdcr_clear |= MDCR_EL2_HPME | MDCR_EL2_MTPME |
- MDCR_EL2_HPMN_MASK;
+ if (!has_hvhe()) {
+ val |= CPTR_NVHE_EL2_RES1;
+ val &= ~(CPTR_NVHE_EL2_RES0);
}
- /* Trap Debug */
- if (!FIELD_GET(ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_DebugVer), feature_ids))
- mdcr_set |= MDCR_EL2_TDRA | MDCR_EL2_TDA | MDCR_EL2_TDE;
-
- /* Trap OS Double Lock */
- if (!FIELD_GET(ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_DoubleLock), feature_ids))
- mdcr_set |= MDCR_EL2_TDOSA;
+ /* Trap AMU */
+ if (!FIELD_GET(ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_AMU), id_aa64pfr0))
+ val |= CPTR_EL2_TAM;
- /* Trap SPE */
- if (!FIELD_GET(ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_PMSVer), feature_ids)) {
- mdcr_set |= MDCR_EL2_TPMS;
- mdcr_clear |= MDCR_EL2_E2PB_MASK << MDCR_EL2_E2PB_SHIFT;
+ /* Trap SVE */
+ if (!FIELD_GET(ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_SVE), id_aa64pfr0)) {
+ if (has_hvhe())
+ val &= ~(CPACR_ELx_ZEN);
+ else
+ val |= CPTR_EL2_TZ;
}
- /* Trap Trace Filter */
- if (!FIELD_GET(ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_TraceFilt), feature_ids))
- mdcr_set |= MDCR_EL2_TTRF;
+ /* No SME support in KVM. */
+ BUG_ON(FIELD_GET(ARM64_FEATURE_MASK(ID_AA64PFR1_EL1_SME), id_aa64pfr1));
+ if (has_hvhe())
+ val &= ~(CPACR_ELx_SMEN);
+ else
+ val |= CPTR_EL2_TSM;
/* Trap Trace */
- if (!FIELD_GET(ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_TraceVer), feature_ids)) {
+ if (!FIELD_GET(ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_TraceVer), id_aa64dfr0)) {
if (has_hvhe())
- cptr_set |= CPACR_EL1_TTA;
+ val |= CPACR_EL1_TTA;
else
- cptr_set |= CPTR_EL2_TTA;
+ val |= CPTR_EL2_TTA;
}
- /* Trap External Trace */
- if (!FIELD_GET(ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_ExtTrcBuff), feature_ids))
- mdcr_clear |= MDCR_EL2_E2TB_MASK << MDCR_EL2_E2TB_SHIFT;
-
- vcpu->arch.mdcr_el2 |= mdcr_set;
- vcpu->arch.mdcr_el2 &= ~mdcr_clear;
- vcpu->arch.cptr_el2 |= cptr_set;
-}
-
-/*
- * Set trap register values based on features in ID_AA64MMFR0.
- */
-static void pvm_init_traps_aa64mmfr0(struct kvm_vcpu *vcpu)
-{
- const u64 feature_ids = pvm_read_id_reg(vcpu, SYS_ID_AA64MMFR0_EL1);
- u64 mdcr_set = 0;
-
- /* Trap Debug Communications Channel registers */
- if (!FIELD_GET(ARM64_FEATURE_MASK(ID_AA64MMFR0_EL1_FGT), feature_ids))
- mdcr_set |= MDCR_EL2_TDCC;
-
- vcpu->arch.mdcr_el2 |= mdcr_set;
+ vcpu->arch.cptr_el2 = val;
}
-/*
- * Set trap register values based on features in ID_AA64MMFR1.
- */
-static void pvm_init_traps_aa64mmfr1(struct kvm_vcpu *vcpu)
-{
- const u64 feature_ids = pvm_read_id_reg(vcpu, SYS_ID_AA64MMFR1_EL1);
- u64 hcr_set = 0;
-
- /* Trap LOR */
- if (!FIELD_GET(ARM64_FEATURE_MASK(ID_AA64MMFR1_EL1_LO), feature_ids))
- hcr_set |= HCR_TLOR;
-
- vcpu->arch.hcr_el2 |= hcr_set;
-}
-
-/*
- * Set baseline trap register values.
- */
-static void pvm_init_trap_regs(struct kvm_vcpu *vcpu)
+static void pvm_init_traps_mdcr(struct kvm_vcpu *vcpu)
{
- const u64 hcr_trap_feat_regs = HCR_TID3;
- const u64 hcr_trap_impdef = HCR_TACR | HCR_TIDCP | HCR_TID1;
-
- /*
- * Always trap:
- * - Feature id registers: to control features exposed to guests
- * - Implementation-defined features
- */
- vcpu->arch.hcr_el2 |= hcr_trap_feat_regs | hcr_trap_impdef;
+ const u64 id_aa64dfr0 = pvm_read_id_reg(vcpu, SYS_ID_AA64DFR0_EL1);
+ const u64 id_aa64mmfr0 = pvm_read_id_reg(vcpu, SYS_ID_AA64MMFR0_EL1);
+ u64 val = vcpu->arch.mdcr_el2;
- /* Clear res0 and set res1 bits to trap potential new features. */
- vcpu->arch.hcr_el2 &= ~(HCR_RES0);
- vcpu->arch.mdcr_el2 &= ~(MDCR_EL2_RES0);
- if (!has_hvhe()) {
- vcpu->arch.cptr_el2 |= CPTR_NVHE_EL2_RES1;
- vcpu->arch.cptr_el2 &= ~(CPTR_NVHE_EL2_RES0);
+ /* Trap/constrain PMU */
+ if (!FIELD_GET(ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_PMUVer), id_aa64dfr0)) {
+ val |= MDCR_EL2_TPM | MDCR_EL2_TPMCR;
+ val &= ~(MDCR_EL2_HPME | MDCR_EL2_MTPME | MDCR_EL2_HPMN_MASK);
}
-}
-static void pkvm_vcpu_reset_hcr(struct kvm_vcpu *vcpu)
-{
- vcpu->arch.hcr_el2 = HCR_GUEST_FLAGS;
+ /* Trap Debug */
+ if (!FIELD_GET(ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_DebugVer), id_aa64dfr0))
+ val |= MDCR_EL2_TDRA | MDCR_EL2_TDA;
- if (has_hvhe())
- vcpu->arch.hcr_el2 |= HCR_E2H;
+ /* Trap OS Double Lock */
+ if (!FIELD_GET(ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_DoubleLock), id_aa64dfr0))
+ val |= MDCR_EL2_TDOSA;
- if (cpus_have_final_cap(ARM64_HAS_RAS_EXTN)) {
- /* route synchronous external abort exceptions to EL2 */
- vcpu->arch.hcr_el2 |= HCR_TEA;
- /* trap error record accesses */
- vcpu->arch.hcr_el2 |= HCR_TERR;
+ /* Trap SPE */
+ if (!FIELD_GET(ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_PMSVer), id_aa64dfr0)) {
+ val |= MDCR_EL2_TPMS;
+ val &= ~(MDCR_EL2_E2PB_MASK << MDCR_EL2_E2PB_SHIFT);
}
- if (cpus_have_final_cap(ARM64_HAS_STAGE2_FWB))
- vcpu->arch.hcr_el2 |= HCR_FWB;
+ /* Trap Trace Filter */
+ if (!FIELD_GET(ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_TraceFilt), id_aa64dfr0))
+ val |= MDCR_EL2_TTRF;
- if (cpus_have_final_cap(ARM64_HAS_EVT) &&
- !cpus_have_final_cap(ARM64_MISMATCHED_CACHE_TYPE))
- vcpu->arch.hcr_el2 |= HCR_TID4;
- else
- vcpu->arch.hcr_el2 |= HCR_TID2;
+ /* Trap External Trace */
+ if (!FIELD_GET(ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_ExtTrcBuff), id_aa64dfr0))
+ val |= MDCR_EL2_E2TB_MASK << MDCR_EL2_E2TB_SHIFT;
- if (vcpu_has_ptrauth(vcpu))
- vcpu->arch.hcr_el2 |= (HCR_API | HCR_APK);
+ /* Trap Debug Communications Channel registers */
+ if (!FIELD_GET(ARM64_FEATURE_MASK(ID_AA64MMFR0_EL1_FGT), id_aa64mmfr0))
+ val |= MDCR_EL2_TDCC;
+
+ vcpu->arch.mdcr_el2 = val;
}
/*
* Initialize trap register values in protected mode.
*/
-static void pkvm_vcpu_init_traps(struct kvm_vcpu *vcpu)
+static void pkvm_vcpu_init_traps(struct pkvm_hyp_vcpu *hyp_vcpu)
{
+ struct kvm_vcpu *vcpu = &hyp_vcpu->vcpu;
+
vcpu->arch.cptr_el2 = kvm_get_reset_cptr_el2(vcpu);
vcpu->arch.mdcr_el2 = 0;
pkvm_vcpu_reset_hcr(vcpu);
- if ((!vcpu_is_protected(vcpu)))
+ if ((!pkvm_hyp_vcpu_is_protected(hyp_vcpu)))
return;
- pvm_init_trap_regs(vcpu);
- pvm_init_traps_aa64pfr0(vcpu);
- pvm_init_traps_aa64pfr1(vcpu);
- pvm_init_traps_aa64dfr0(vcpu);
- pvm_init_traps_aa64mmfr0(vcpu);
- pvm_init_traps_aa64mmfr1(vcpu);
+ /*
+ * PAuth is allowed if supported by the system and the vcpu.
+ * Properly checking for PAuth requires checking various fields in
+ * ID_AA64ISAR1_EL1 and ID_AA64ISAR2_EL1. The way that fixed config
+ * is controlled now in pKVM does not easily allow that. This will
+ * change later to follow the changes upstream wrt fixed configuration
+ * and nested virt.
+ */
+ BUILD_BUG_ON(!FIELD_GET(ARM64_FEATURE_MASK(ID_AA64ISAR1_EL1_GPI),
+ PVM_ID_AA64ISAR1_ALLOW));
+
+ /* Protected KVM does not support AArch32 guests. */
+ BUILD_BUG_ON(FIELD_GET(ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_EL0),
+ PVM_ID_AA64PFR0_ALLOW) != ID_AA64PFR0_EL1_EL0_IMP);
+ BUILD_BUG_ON(FIELD_GET(ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_EL1),
+ PVM_ID_AA64PFR0_ALLOW) != ID_AA64PFR0_EL1_EL1_IMP);
+
+ /*
+ * Linux guests assume support for floating-point and Advanced SIMD. Do
+ * not change the trapping behavior for these from the KVM default.
+ */
+ BUILD_BUG_ON(!FIELD_GET(ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_FP),
+ PVM_ID_AA64PFR0_ALLOW));
+ BUILD_BUG_ON(!FIELD_GET(ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_AdvSIMD),
+ PVM_ID_AA64PFR0_ALLOW));
+
+ pvm_init_traps_hcr(vcpu);
+ pvm_init_traps_cptr(vcpu);
+ pvm_init_traps_mdcr(vcpu);
}
/*
@@ -448,7 +419,7 @@ static int init_pkvm_hyp_vcpu(struct pkvm_hyp_vcpu *hyp_vcpu,
pkvm_vcpu_init_sve(hyp_vcpu, host_vcpu);
pkvm_vcpu_init_ptrauth(hyp_vcpu);
- pkvm_vcpu_init_traps(&hyp_vcpu->vcpu);
+ pkvm_vcpu_init_traps(hyp_vcpu);
done:
if (ret)
unpin_host_vcpu(host_vcpu);
--
2.47.0.338.g60cca15819-goog
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