diff options
author | James Morse <james.morse@arm.com> | 2024-02-28 13:49:10 +0000 |
---|---|---|
committer | James Morse <james.morse@arm.com> | 2024-03-21 16:39:47 +0000 |
commit | efef6777cd47f54b38b9f5c02a0d891eb54ce198 (patch) | |
tree | 56d7feab130e6585cd2be1227c3139b641d35ee9 | |
parent | 319adc40ecad74fc8d18439d621b902b47c39abc (diff) | |
download | linux-mpam/kvm_mpam_fix/v3.tar.gz |
KVM: arm64: selftests: Test ID_AA64PFR0.MPAM isn't completely ignoredmpam/kvm_mpam_fix/v3
The ID_AA64PFR0.MPAM bit was previously accidentally exposed to guests,
and is ignored by KVM. KVM will always present the guest with 0 here,
and trap the MPAM system registers to inject an undef.
But, this vaulue is still needed to prevent migration when the value
is incompatible with the target hardware. Add a kvm unit test to try
and write multiple values to ID_AA64PFR0.MPAM. Only the hardware value
previously exposed should be ignored, all other values should be
rejected.
Signed-off-by: James Morse <james.morse@arm.com>
-rw-r--r-- | tools/testing/selftests/kvm/aarch64/set_id_regs.c | 53 |
1 files changed, 52 insertions, 1 deletions
diff --git a/tools/testing/selftests/kvm/aarch64/set_id_regs.c b/tools/testing/selftests/kvm/aarch64/set_id_regs.c index b42a0dc19852a8..fbb600111969d4 100644 --- a/tools/testing/selftests/kvm/aarch64/set_id_regs.c +++ b/tools/testing/selftests/kvm/aarch64/set_id_regs.c @@ -426,6 +426,56 @@ static void test_user_set_reg(struct kvm_vcpu *vcpu, bool aarch64_only) } } +#define MPAM_IDREG_TEST 1 +static void test_user_set_mpam_reg(struct kvm_vcpu *vcpu) +{ + uint64_t masks[KVM_ARM_FEATURE_ID_RANGE_SIZE]; + struct reg_mask_range range = { + .addr = (__u64)masks, + }; + uint64_t val, ftr_mask; + int idx, err; + + /* + * If ID_AA64PFR0.MPAM is _not_ officially modifiable and is zero, + * check that if it can be set to 1, (i.e. it is supported by the + * hardware), that it can't be set to other values. + */ + + /* Get writable masks for feature ID registers */ + memset(range.reserved, 0, sizeof(range.reserved)); + vm_ioctl(vcpu->vm, KVM_ARM_GET_REG_WRITABLE_MASKS, &range); + + /* Writeable? Nothing to test! */ + idx = sys_reg_to_idx(SYS_ID_AA64PFR0_EL1); + ftr_mask = ID_AA64PFR0_EL1_MPAM_MASK; + if ((masks[idx] & ftr_mask) == ftr_mask) { + ksft_test_result_skip("ID_AA64PFR0.MPAM is officially writable, nothing to test\n"); + return; + } + + /* Get the id register value */ + vcpu_get_reg(vcpu, KVM_ARM64_SYS_REG(SYS_ID_AA64PFR0_EL1), &val); + + /* Try to set MPAM=1 */ + val &= ~GENMASK_ULL(44, 40); + val |= FIELD_PREP(GENMASK_ULL(44, 40), 1); + err = __vcpu_set_reg(vcpu, KVM_ARM64_SYS_REG(SYS_ID_AA64PFR0_EL1), val); + if (err) { + ksft_test_result_skip("ID_AA64PFR0.MPAM is not writable, nothing to test\n"); + return; + } + + /* Try to set MPAM=2 */ + val &= ~GENMASK_ULL(43, 40); + val |= FIELD_PREP(GENMASK_ULL(43, 40), 2); + err = __vcpu_set_reg(vcpu, KVM_ARM64_SYS_REG(SYS_ID_AA64PFR0_EL1), val); + if (err == -EPERM) + ksft_test_result_pass("ID_AA64PFR0_EL1.MPAM not arbitrarily modifiable\n"); + else + ksft_test_result_fail("ID_AA64PFR0_EL1.MPAM value should not be ignored\n"); +} + static void test_guest_reg_read(struct kvm_vcpu *vcpu) { bool done = false; @@ -477,12 +527,13 @@ int main(void) ARRAY_SIZE(ftr_id_aa64isar2_el1) + ARRAY_SIZE(ftr_id_aa64pfr0_el1) + ARRAY_SIZE(ftr_id_aa64mmfr0_el1) + ARRAY_SIZE(ftr_id_aa64mmfr1_el1) + ARRAY_SIZE(ftr_id_aa64mmfr2_el1) + ARRAY_SIZE(ftr_id_aa64zfr0_el1) - - ARRAY_SIZE(test_regs); + ARRAY_SIZE(test_regs) + MPAM_IDREG_TEST; ksft_set_plan(ftr_cnt); test_user_set_reg(vcpu, aarch64_only); test_guest_reg_read(vcpu); + test_user_set_mpam_reg(vcpu); kvm_vm_free(vm); |