Early versions of Cortex-A76 can end-up with corrupt TLBs if they speculate an AT instruction in during a guest switch while the S1/S2 system registers are in an inconsistent state.
Work around it by: - Mandating VHE - Make sure that S1 and S2 system registers are consistent before clearing HCR_EL2.TGE, which allows AT to target the EL1 translation regime These two things together ensure that we cannot hit this erratum. Signed-off-by: Marc Zyngier <[email protected]> --- Documentation/arm64/silicon-errata.txt | 1 + arch/arm64/Kconfig | 12 ++++++++++++ arch/arm64/include/asm/cpucaps.h | 3 ++- arch/arm64/include/asm/kvm_host.h | 3 +++ arch/arm64/include/asm/kvm_hyp.h | 6 ++++++ arch/arm64/kernel/cpu_errata.c | 8 ++++++++ arch/arm64/kvm/hyp/switch.c | 14 ++++++++++++++ 7 files changed, 46 insertions(+), 1 deletion(-) diff --git a/Documentation/arm64/silicon-errata.txt b/Documentation/arm64/silicon-errata.txt index 76ccded8b74c..04f0bc4690c6 100644 --- a/Documentation/arm64/silicon-errata.txt +++ b/Documentation/arm64/silicon-errata.txt @@ -57,6 +57,7 @@ stable kernels. | ARM | Cortex-A73 | #858921 | ARM64_ERRATUM_858921 | | ARM | Cortex-A55 | #1024718 | ARM64_ERRATUM_1024718 | | ARM | Cortex-A76 | #1188873 | ARM64_ERRATUM_1188873 | +| ARM | Cortex-A76 | #1165522 | ARM64_ERRATUM_1165522 | | ARM | MMU-500 | #841119,#826419 | N/A | | | | | | | Cavium | ThunderX ITS | #22375, #24313 | CAVIUM_ERRATUM_22375 | diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index 787d7850e064..a68bc6cc2167 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -497,6 +497,18 @@ config ARM64_ERRATUM_1188873 If unsure, say Y. +config ARM64_ERRATUM_1165522 + bool "Cortex-A76: Speculative AT instruction using out-of-context translation regime could cause subsequent request to generate an incorrect translation" + default y + help + This option adds work arounds for ARM Cortex-A76 erratum 1165522 + + Affected Cortex-A76 cores (r0p0, r1p0, r2p0) could end-up with + corrupted TLBs by speculating an AT instruction during a guest + context switch. + + If unsure, say Y. + config CAVIUM_ERRATUM_22375 bool "Cavium erratum 22375, 24313" default y diff --git a/arch/arm64/include/asm/cpucaps.h b/arch/arm64/include/asm/cpucaps.h index 6e2d254c09eb..62d8cd15fdf2 100644 --- a/arch/arm64/include/asm/cpucaps.h +++ b/arch/arm64/include/asm/cpucaps.h @@ -54,7 +54,8 @@ #define ARM64_HAS_CRC32 33 #define ARM64_SSBS 34 #define ARM64_WORKAROUND_1188873 35 +#define ARM64_WORKAROUND_1165522 36 -#define ARM64_NCAPS 36 +#define ARM64_NCAPS 37 #endif /* __ASM_CPUCAPS_H */ diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h index 7d6e974d024a..8f486026ac87 100644 --- a/arch/arm64/include/asm/kvm_host.h +++ b/arch/arm64/include/asm/kvm_host.h @@ -435,6 +435,9 @@ static inline bool kvm_arch_sve_requires_vhe(void) static inline bool kvm_arch_impl_requires_vhe(void) { /* Some implementations have defects that confine them to VHE */ + if (cpus_have_cap(ARM64_WORKAROUND_1165522)) + return true; + return false; } diff --git a/arch/arm64/include/asm/kvm_hyp.h b/arch/arm64/include/asm/kvm_hyp.h index 23aca66767f9..9681360d0959 100644 --- a/arch/arm64/include/asm/kvm_hyp.h +++ b/arch/arm64/include/asm/kvm_hyp.h @@ -163,6 +163,12 @@ static __always_inline void __hyp_text __load_guest_stage2(struct kvm *kvm) { write_sysreg(kvm->arch.vtcr, vtcr_el2); write_sysreg(kvm->arch.vttbr, vttbr_el2); + + /* + * ARM erratum 1165522 requires the actual execution of the + * above before we can switch to the guest translation regime. + */ + asm(ALTERNATIVE("nop", "isb", ARM64_WORKAROUND_1165522)); } #endif /* __ARM64_KVM_HYP_H__ */ diff --git a/arch/arm64/kernel/cpu_errata.c b/arch/arm64/kernel/cpu_errata.c index a509e35132d2..476e738e6c46 100644 --- a/arch/arm64/kernel/cpu_errata.c +++ b/arch/arm64/kernel/cpu_errata.c @@ -739,6 +739,14 @@ const struct arm64_cpu_capabilities arm64_errata[] = { .capability = ARM64_WORKAROUND_1188873, ERRATA_MIDR_RANGE(MIDR_CORTEX_A76, 0, 0, 2, 0), }, +#endif +#ifdef CONFIG_ARM64_ERRATUM_1165522 + { + /* Cortex-A76 r0p0 to r2p0 */ + .desc = "ARM erratum 1165522", + .capability = ARM64_WORKAROUND_1165522, + ERRATA_MIDR_RANGE(MIDR_CORTEX_A76, 0, 0, 2, 0), + }, #endif { } diff --git a/arch/arm64/kvm/hyp/switch.c b/arch/arm64/kvm/hyp/switch.c index 51d5d966d9e5..322109183853 100644 --- a/arch/arm64/kvm/hyp/switch.c +++ b/arch/arm64/kvm/hyp/switch.c @@ -143,6 +143,13 @@ static void deactivate_traps_vhe(void) { extern char vectors[]; /* kernel exception vectors */ write_sysreg(HCR_HOST_VHE_FLAGS, hcr_el2); + + /* + * ARM erratum 1165522 requires the actual execution of the + * above before we can switch to the host translation regime. + */ + asm(ALTERNATIVE("nop", "isb", ARM64_WORKAROUND_1165522)); + write_sysreg(CPACR_EL1_DEFAULT, cpacr_el1); write_sysreg(vectors, vbar_el1); } @@ -499,6 +506,13 @@ int kvm_vcpu_run_vhe(struct kvm_vcpu *vcpu) sysreg_save_host_state_vhe(host_ctxt); + /* + * ARM erratum 1165522 requires us to have all the translation + * context in place before we clear HCR_TGE. All the offending + * guest sysregs are loaded in kvm_vcpu_load_sysregs, and + * __activate_vm has the stage-2 configuration. Once this is + * done, __activate_trap clears HCR_TGE (among other things). + */ __activate_vm(vcpu->kvm); __activate_traps(vcpu); -- 2.19.1 _______________________________________________ kvmarm mailing list [email protected] https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
