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authorPaolo Bonzini <pbonzini@redhat.com>2020-11-13 06:28:23 -0500
committerPaolo Bonzini <pbonzini@redhat.com>2020-11-13 06:28:23 -0500
commit2c38234c425e627ca493eb0b7a9a34899a1f03ef (patch)
treecdb9c1a7466541643e2d22bc8c69aa8183a0f4fd /arch
parent585e5b17b92dead8a3aca4e3c9876fbca5f7e0ba (diff)
parented4ffaf49bf9ce1002b516d8c6aa04937b7950bc (diff)
downloadlinux-2c38234c425e627ca493eb0b7a9a34899a1f03ef.tar.bz2
Merge tag 'kvmarm-fixes-5.10-3' of git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD
KVM/arm64 fixes for v5.10, take #3 - Allow userspace to downgrade ID_AA64PFR0_EL1.CSV2 - Inject UNDEF on SCXTNUM_ELx access
Diffstat (limited to 'arch')
-rw-r--r--arch/arm64/include/asm/kvm_host.h2
-rw-r--r--arch/arm64/include/asm/sysreg.h4
-rw-r--r--arch/arm64/kvm/arm.c16
-rw-r--r--arch/arm64/kvm/sys_regs.c111
4 files changed, 89 insertions, 44 deletions
diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index 781d029b8aa8..0cd9f0f75c13 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -118,6 +118,8 @@ struct kvm_arch {
*/
unsigned long *pmu_filter;
unsigned int pmuver;
+
+ u8 pfr0_csv2;
};
struct kvm_vcpu_fault_info {
diff --git a/arch/arm64/include/asm/sysreg.h b/arch/arm64/include/asm/sysreg.h
index 174817ba119c..e2ef4c2edf06 100644
--- a/arch/arm64/include/asm/sysreg.h
+++ b/arch/arm64/include/asm/sysreg.h
@@ -372,6 +372,8 @@
#define SYS_CONTEXTIDR_EL1 sys_reg(3, 0, 13, 0, 1)
#define SYS_TPIDR_EL1 sys_reg(3, 0, 13, 0, 4)
+#define SYS_SCXTNUM_EL1 sys_reg(3, 0, 13, 0, 7)
+
#define SYS_CNTKCTL_EL1 sys_reg(3, 0, 14, 1, 0)
#define SYS_CCSIDR_EL1 sys_reg(3, 1, 0, 0, 0)
@@ -404,6 +406,8 @@
#define SYS_TPIDR_EL0 sys_reg(3, 3, 13, 0, 2)
#define SYS_TPIDRRO_EL0 sys_reg(3, 3, 13, 0, 3)
+#define SYS_SCXTNUM_EL0 sys_reg(3, 3, 13, 0, 7)
+
/* Definitions for system register interface to AMU for ARMv8.4 onwards */
#define SYS_AM_EL0(crm, op2) sys_reg(3, 3, 13, (crm), (op2))
#define SYS_AMCR_EL0 SYS_AM_EL0(2, 0)
diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index 5750ec34960e..c0ffb019ca8b 100644
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -102,6 +102,20 @@ static int kvm_arm_default_max_vcpus(void)
return vgic_present ? kvm_vgic_get_max_vcpus() : KVM_MAX_VCPUS;
}
+static void set_default_csv2(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;
+}
+
/**
* kvm_arch_init_vm - initializes a VM data structure
* @kvm: pointer to the KVM struct
@@ -127,6 +141,8 @@ 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->arch.max_vcpus = kvm_arm_default_max_vcpus();
+ set_default_csv2(kvm);
+
return ret;
out_free_stage2_pgd:
kvm_free_stage2_pgd(&kvm->arch.mmu);
diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index d0868d0e8ff4..c1fac9836af1 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -1038,8 +1038,8 @@ static bool access_pmuserenr(struct kvm_vcpu *vcpu, struct sys_reg_params *p,
{ SYS_DESC(SYS_PMEVTYPERn_EL0(n)), \
access_pmu_evtyper, reset_unknown, (PMEVTYPER0_EL0 + n), }
-static bool access_amu(struct kvm_vcpu *vcpu, struct sys_reg_params *p,
- const struct sys_reg_desc *r)
+static bool undef_access(struct kvm_vcpu *vcpu, struct sys_reg_params *p,
+ const struct sys_reg_desc *r)
{
kvm_inject_undefined(vcpu);
@@ -1047,24 +1047,10 @@ static bool access_amu(struct kvm_vcpu *vcpu, struct sys_reg_params *p,
}
/* Macro to expand the AMU counter and type registers*/
-#define AMU_AMEVCNTR0_EL0(n) { SYS_DESC(SYS_AMEVCNTR0_EL0(n)), access_amu }
-#define AMU_AMEVTYPER0_EL0(n) { SYS_DESC(SYS_AMEVTYPER0_EL0(n)), access_amu }
-#define AMU_AMEVCNTR1_EL0(n) { SYS_DESC(SYS_AMEVCNTR1_EL0(n)), access_amu }
-#define AMU_AMEVTYPER1_EL0(n) { SYS_DESC(SYS_AMEVTYPER1_EL0(n)), access_amu }
-
-static bool trap_ptrauth(struct kvm_vcpu *vcpu,
- struct sys_reg_params *p,
- const struct sys_reg_desc *rd)
-{
- /*
- * If we land here, that is because we didn't fixup the access on exit
- * by allowing the PtrAuth sysregs. The only way this happens is when
- * the guest does not have PtrAuth support enabled.
- */
- kvm_inject_undefined(vcpu);
-
- return false;
-}
+#define AMU_AMEVCNTR0_EL0(n) { SYS_DESC(SYS_AMEVCNTR0_EL0(n)), undef_access }
+#define AMU_AMEVTYPER0_EL0(n) { SYS_DESC(SYS_AMEVTYPER0_EL0(n)), undef_access }
+#define AMU_AMEVCNTR1_EL0(n) { SYS_DESC(SYS_AMEVCNTR1_EL0(n)), undef_access }
+#define AMU_AMEVTYPER1_EL0(n) { SYS_DESC(SYS_AMEVTYPER1_EL0(n)), undef_access }
static unsigned int ptrauth_visibility(const struct kvm_vcpu *vcpu,
const struct sys_reg_desc *rd)
@@ -1072,8 +1058,14 @@ static unsigned int ptrauth_visibility(const struct kvm_vcpu *vcpu,
return vcpu_has_ptrauth(vcpu) ? 0 : REG_HIDDEN;
}
+/*
+ * If we land here on a PtrAuth access, that is because we didn't
+ * fixup the access on exit by allowing the PtrAuth sysregs. The only
+ * way this happens is when the guest does not have PtrAuth support
+ * enabled.
+ */
#define __PTRAUTH_KEY(k) \
- { SYS_DESC(SYS_## k), trap_ptrauth, reset_unknown, k, \
+ { SYS_DESC(SYS_## k), undef_access, reset_unknown, k, \
.visibility = ptrauth_visibility}
#define PTRAUTH_KEY(k) \
@@ -1128,9 +1120,8 @@ static u64 read_id_reg(const struct kvm_vcpu *vcpu,
if (!vcpu_has_sve(vcpu))
val &= ~(0xfUL << ID_AA64PFR0_SVE_SHIFT);
val &= ~(0xfUL << ID_AA64PFR0_AMU_SHIFT);
- if (!(val & (0xfUL << ID_AA64PFR0_CSV2_SHIFT)) &&
- arm64_get_spectre_v2_state() == SPECTRE_UNAFFECTED)
- val |= (1UL << ID_AA64PFR0_CSV2_SHIFT);
+ val &= ~(0xfUL << ID_AA64PFR0_CSV2_SHIFT);
+ val |= ((u64)vcpu->kvm->arch.pfr0_csv2 << ID_AA64PFR0_CSV2_SHIFT);
} else if (id == SYS_ID_AA64PFR1_EL1) {
val &= ~(0xfUL << ID_AA64PFR1_MTE_SHIFT);
} else if (id == SYS_ID_AA64ISAR1_EL1 && !vcpu_has_ptrauth(vcpu)) {
@@ -1213,6 +1204,40 @@ 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,
+ const struct kvm_one_reg *reg, void __user *uaddr)
+{
+ const u64 id = sys_reg_to_index(rd);
+ int err;
+ u64 val;
+ u8 csv2;
+
+ err = reg_from_user(&val, uaddr, id);
+ if (err)
+ return err;
+
+ /*
+ * 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_CSV2_SHIFT);
+ if (csv2 > 1 ||
+ (csv2 && arm64_get_spectre_v2_state() != SPECTRE_UNAFFECTED))
+ return -EINVAL;
+
+ /* We can only differ with CSV2, and anything else is an error */
+ val ^= read_id_reg(vcpu, rd, false);
+ val &= ~(0xFUL << ID_AA64PFR0_CSV2_SHIFT);
+ if (val)
+ return -EINVAL;
+
+ vcpu->kvm->arch.pfr0_csv2 = csv2;
+
+ return 0;
+}
+
/*
* cpufeature ID register user accessors
*
@@ -1341,13 +1366,6 @@ static bool access_ccsidr(struct kvm_vcpu *vcpu, struct sys_reg_params *p,
return true;
}
-static bool access_mte_regs(struct kvm_vcpu *vcpu, struct sys_reg_params *p,
- const struct sys_reg_desc *r)
-{
- kvm_inject_undefined(vcpu);
- return false;
-}
-
/* sys_reg_desc initialiser for known cpufeature ID registers */
#define ID_SANITISED(name) { \
SYS_DESC(SYS_##name), \
@@ -1472,7 +1490,8 @@ static const struct sys_reg_desc sys_reg_descs[] = {
/* AArch64 ID registers */
/* CRm=4 */
- ID_SANITISED(ID_AA64PFR0_EL1),
+ { 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),
@@ -1515,8 +1534,8 @@ static const struct sys_reg_desc sys_reg_descs[] = {
{ SYS_DESC(SYS_ACTLR_EL1), access_actlr, reset_actlr, ACTLR_EL1 },
{ SYS_DESC(SYS_CPACR_EL1), NULL, reset_val, CPACR_EL1, 0 },
- { SYS_DESC(SYS_RGSR_EL1), access_mte_regs },
- { SYS_DESC(SYS_GCR_EL1), access_mte_regs },
+ { SYS_DESC(SYS_RGSR_EL1), undef_access },
+ { SYS_DESC(SYS_GCR_EL1), undef_access },
{ SYS_DESC(SYS_ZCR_EL1), NULL, reset_val, ZCR_EL1, 0, .visibility = sve_visibility },
{ SYS_DESC(SYS_TTBR0_EL1), access_vm_reg, reset_unknown, TTBR0_EL1 },
@@ -1542,8 +1561,8 @@ static const struct sys_reg_desc sys_reg_descs[] = {
{ SYS_DESC(SYS_ERXMISC0_EL1), trap_raz_wi },
{ SYS_DESC(SYS_ERXMISC1_EL1), trap_raz_wi },
- { SYS_DESC(SYS_TFSR_EL1), access_mte_regs },
- { SYS_DESC(SYS_TFSRE0_EL1), access_mte_regs },
+ { SYS_DESC(SYS_TFSR_EL1), undef_access },
+ { SYS_DESC(SYS_TFSRE0_EL1), undef_access },
{ SYS_DESC(SYS_FAR_EL1), access_vm_reg, reset_unknown, FAR_EL1 },
{ SYS_DESC(SYS_PAR_EL1), NULL, reset_unknown, PAR_EL1 },
@@ -1579,6 +1598,8 @@ static const struct sys_reg_desc sys_reg_descs[] = {
{ SYS_DESC(SYS_CONTEXTIDR_EL1), access_vm_reg, reset_val, CONTEXTIDR_EL1, 0 },
{ SYS_DESC(SYS_TPIDR_EL1), NULL, reset_unknown, TPIDR_EL1 },
+ { SYS_DESC(SYS_SCXTNUM_EL1), undef_access },
+
{ SYS_DESC(SYS_CNTKCTL_EL1), NULL, reset_val, CNTKCTL_EL1, 0},
{ SYS_DESC(SYS_CCSIDR_EL1), access_ccsidr },
@@ -1607,14 +1628,16 @@ static const struct sys_reg_desc sys_reg_descs[] = {
{ SYS_DESC(SYS_TPIDR_EL0), NULL, reset_unknown, TPIDR_EL0 },
{ SYS_DESC(SYS_TPIDRRO_EL0), NULL, reset_unknown, TPIDRRO_EL0 },
- { SYS_DESC(SYS_AMCR_EL0), access_amu },
- { SYS_DESC(SYS_AMCFGR_EL0), access_amu },
- { SYS_DESC(SYS_AMCGCR_EL0), access_amu },
- { SYS_DESC(SYS_AMUSERENR_EL0), access_amu },
- { SYS_DESC(SYS_AMCNTENCLR0_EL0), access_amu },
- { SYS_DESC(SYS_AMCNTENSET0_EL0), access_amu },
- { SYS_DESC(SYS_AMCNTENCLR1_EL0), access_amu },
- { SYS_DESC(SYS_AMCNTENSET1_EL0), access_amu },
+ { SYS_DESC(SYS_SCXTNUM_EL0), undef_access },
+
+ { SYS_DESC(SYS_AMCR_EL0), undef_access },
+ { SYS_DESC(SYS_AMCFGR_EL0), undef_access },
+ { SYS_DESC(SYS_AMCGCR_EL0), undef_access },
+ { SYS_DESC(SYS_AMUSERENR_EL0), undef_access },
+ { SYS_DESC(SYS_AMCNTENCLR0_EL0), undef_access },
+ { SYS_DESC(SYS_AMCNTENSET0_EL0), undef_access },
+ { SYS_DESC(SYS_AMCNTENCLR1_EL0), undef_access },
+ { SYS_DESC(SYS_AMCNTENSET1_EL0), undef_access },
AMU_AMEVCNTR0_EL0(0),
AMU_AMEVCNTR0_EL0(1),
AMU_AMEVCNTR0_EL0(2),