[PATCH v4 06/14] KVM: arm64: Set protected VM traps based on its view of feature registers
Fuad Tabba
tabba at google.com
Mon Dec 2 07:47:33 PST 2024
Now that the VM's feature id registers are initialized with the
values of the supported features, use those values to determine
which traps to set using kvm_has_feature().
Signed-off-by: Fuad Tabba <tabba at google.com>
---
arch/arm64/kvm/hyp/nvhe/pkvm.c | 85 +++++++++++-------------------
arch/arm64/kvm/hyp/nvhe/sys_regs.c | 7 ---
2 files changed, 30 insertions(+), 62 deletions(-)
diff --git a/arch/arm64/kvm/hyp/nvhe/pkvm.c b/arch/arm64/kvm/hyp/nvhe/pkvm.c
index 4ef03294b2b4..3b4ea97148b9 100644
--- a/arch/arm64/kvm/hyp/nvhe/pkvm.c
+++ b/arch/arm64/kvm/hyp/nvhe/pkvm.c
@@ -52,9 +52,7 @@ static void pkvm_vcpu_reset_hcr(struct kvm_vcpu *vcpu)
static void pvm_init_traps_hcr(struct kvm_vcpu *vcpu)
{
- 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);
+ struct kvm *kvm = vcpu->kvm;
u64 val = vcpu->arch.hcr_el2;
/* No support for AArch32. */
@@ -70,25 +68,20 @@ static void pvm_init_traps_hcr(struct kvm_vcpu *vcpu)
*/
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) {
+ if (!kvm_has_feat(kvm, ID_AA64PFR0_EL1, RAS, IMP)) {
val |= HCR_TERR | HCR_TEA;
val &= ~(HCR_FIEN);
}
- /* Trap AMU */
- if (!FIELD_GET(ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_AMU), id_aa64pfr0))
+ if (!kvm_has_feat(kvm, ID_AA64PFR0_EL1, AMU, IMP))
val &= ~(HCR_AMVOFFEN);
- /* Memory Tagging: Trap and Treat as Untagged if not supported. */
- if (!FIELD_GET(ARM64_FEATURE_MASK(ID_AA64PFR1_EL1_MTE), id_aa64pfr1)) {
+ if (!kvm_has_feat(kvm, ID_AA64PFR1_EL1, MTE, IMP)) {
val |= HCR_TID5;
val &= ~(HCR_DCT | HCR_ATA);
}
- /* Trap LOR */
- if (!FIELD_GET(ARM64_FEATURE_MASK(ID_AA64MMFR1_EL1_LO), id_aa64mmfr1))
+ if (!kvm_has_feat(kvm, ID_AA64MMFR1_EL1, LO, IMP))
val |= HCR_TLOR;
vcpu->arch.hcr_el2 = val;
@@ -96,9 +89,7 @@ static void pvm_init_traps_hcr(struct kvm_vcpu *vcpu)
static void pvm_init_traps_cptr(struct kvm_vcpu *vcpu)
{
- 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);
+ struct kvm *kvm = vcpu->kvm;
u64 val = vcpu->arch.cptr_el2;
if (!has_hvhe()) {
@@ -106,12 +97,11 @@ static void pvm_init_traps_cptr(struct kvm_vcpu *vcpu)
val &= ~(CPTR_NVHE_EL2_RES0);
}
- /* Trap AMU */
- if (!FIELD_GET(ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_AMU), id_aa64pfr0))
+ if (!kvm_has_feat(kvm, ID_AA64PFR0_EL1, AMU, IMP))
val |= CPTR_EL2_TAM;
- /* Trap SVE */
- if (!FIELD_GET(ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_SVE), id_aa64pfr0)) {
+ /* SVE can be disabled by userspace even if supported. */
+ if (!vcpu_has_sve(vcpu)) {
if (has_hvhe())
val &= ~(CPACR_ELx_ZEN);
else
@@ -119,14 +109,13 @@ static void pvm_init_traps_cptr(struct kvm_vcpu *vcpu)
}
/* No SME support in KVM. */
- BUG_ON(FIELD_GET(ARM64_FEATURE_MASK(ID_AA64PFR1_EL1_SME), id_aa64pfr1));
+ BUG_ON(kvm_has_feat(kvm, ID_AA64PFR1_EL1, SME, IMP));
if (has_hvhe())
val &= ~(CPACR_ELx_SMEN);
else
val |= CPTR_EL2_TSM;
- /* Trap Trace */
- if (!FIELD_GET(ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_TraceVer), id_aa64dfr0)) {
+ if (!kvm_has_feat(kvm, ID_AA64DFR0_EL1, TraceVer, IMP)) {
if (has_hvhe())
val |= CPACR_EL1_TTA;
else
@@ -138,40 +127,33 @@ static void pvm_init_traps_cptr(struct kvm_vcpu *vcpu)
static void pvm_init_traps_mdcr(struct kvm_vcpu *vcpu)
{
- 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);
+ struct kvm *kvm = vcpu->kvm;
u64 val = vcpu->arch.mdcr_el2;
- /* Trap/constrain PMU */
- if (!FIELD_GET(ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_PMUVer), id_aa64dfr0)) {
+ if (!kvm_has_feat(kvm, ID_AA64DFR0_EL1, PMUVer, IMP)) {
val |= MDCR_EL2_TPM | MDCR_EL2_TPMCR;
val &= ~(MDCR_EL2_HPME | MDCR_EL2_MTPME | MDCR_EL2_HPMN_MASK);
}
- /* Trap Debug */
- if (!FIELD_GET(ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_DebugVer), id_aa64dfr0))
+ if (!kvm_has_feat(kvm, ID_AA64DFR0_EL1, DebugVer, IMP))
val |= MDCR_EL2_TDRA | MDCR_EL2_TDA;
- /* Trap OS Double Lock */
- if (!FIELD_GET(ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_DoubleLock), id_aa64dfr0))
+ if (!kvm_has_feat(kvm, ID_AA64DFR0_EL1, DoubleLock, IMP))
val |= MDCR_EL2_TDOSA;
- /* Trap SPE */
- if (!FIELD_GET(ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_PMSVer), id_aa64dfr0)) {
+ if (!kvm_has_feat(kvm, ID_AA64DFR0_EL1, PMSVer, IMP)) {
val |= MDCR_EL2_TPMS;
val &= ~(MDCR_EL2_E2PB_MASK << MDCR_EL2_E2PB_SHIFT);
}
- /* Trap Trace Filter */
- if (!FIELD_GET(ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_TraceFilt), id_aa64dfr0))
+ if (!kvm_has_feat(kvm, ID_AA64DFR0_EL1, TraceFilt, IMP))
val |= MDCR_EL2_TTRF;
- /* Trap External Trace */
- if (!FIELD_GET(ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_ExtTrcBuff), id_aa64dfr0))
+ if (!kvm_has_feat(kvm, ID_AA64DFR0_EL1, ExtTrcBuff, IMP))
val |= MDCR_EL2_E2TB_MASK << MDCR_EL2_E2TB_SHIFT;
/* Trap Debug Communications Channel registers */
- if (!FIELD_GET(ARM64_FEATURE_MASK(ID_AA64MMFR0_EL1_FGT), id_aa64mmfr0))
+ if (!kvm_has_feat(kvm, ID_AA64MMFR0_EL1, FGT, IMP))
val |= MDCR_EL2_TDCC;
vcpu->arch.mdcr_el2 = val;
@@ -183,31 +165,24 @@ static void pvm_init_traps_mdcr(struct kvm_vcpu *vcpu)
*/
static int pkvm_check_pvm_cpu_features(struct kvm_vcpu *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));
+ struct kvm *kvm = vcpu->kvm;
/* 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);
+ if (kvm_has_feat(kvm, ID_AA64PFR0_EL1, EL0, AARCH32) ||
+ kvm_has_feat(kvm, ID_AA64PFR0_EL1, EL1, AARCH32))
+ return -EINVAL;
/*
* 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));
+ if (!kvm_has_feat(kvm, ID_AA64PFR0_EL1, FP, IMP) ||
+ !kvm_has_feat(kvm, ID_AA64PFR0_EL1, AdvSIMD, IMP))
+ return -EINVAL;
+
+ /* No SME support in KVM right now. Check to catch if it changes. */
+ if (kvm_has_feat(kvm, ID_AA64PFR1_EL1, SME, IMP))
+ return -EINVAL;
return 0;
}
diff --git a/arch/arm64/kvm/hyp/nvhe/sys_regs.c b/arch/arm64/kvm/hyp/nvhe/sys_regs.c
index 1261da6a2861..39b678d2c120 100644
--- a/arch/arm64/kvm/hyp/nvhe/sys_regs.c
+++ b/arch/arm64/kvm/hyp/nvhe/sys_regs.c
@@ -285,13 +285,6 @@ static bool pvm_access_id_aarch32(struct kvm_vcpu *vcpu,
return false;
}
- /*
- * No support for AArch32 guests, therefore, pKVM has no sanitized copy
- * of AArch32 feature id registers.
- */
- BUILD_BUG_ON(FIELD_GET(ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_EL1),
- PVM_ID_AA64PFR0_ALLOW) > ID_AA64PFR0_EL1_EL1_IMP);
-
return pvm_access_raz_wi(vcpu, p, r);
}
--
2.47.0.338.g60cca15819-goog
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