Re: [PATCH 25/31] arm64: Add workaround for Cavium Thunder erratum 30115

Auger Eric
2017-05-30T09:56:22Z

Hi,

On 03/05/2017 12:46, Marc Zyngier wrote:
> From: David Daney <david.daney@cavium.com>
>
> Some Cavium Thunder CPUs suffer a problem where a KVM guest may
> inadvertently cause the host kernel to quit receiving interrupts.
>
> Use the Group-0/1 trapping in order to deal with it.
>
> [maz]: Adapted patch to the Group-0/1 trapping, reworked commit log
>
> Signed-off-by: David Daney <david.daney@cavium.com>
> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Reviewed-by: Eric Auger <eric.auger@redhat.com>

Eric
> ---
> Documentation/arm64/silicon-errata.txt | 1 +
> arch/arm64/Kconfig | 11 +++++++++++
> arch/arm64/include/asm/cpucaps.h | 3 ++-
> arch/arm64/kernel/cpu_errata.c | 21 +++++++++++++++++++++
> virt/kvm/arm/vgic/vgic-v3.c | 7 +++++++
> 5 files changed, 42 insertions(+), 1 deletion(-)
>
> diff --git a/Documentation/arm64/silicon-errata.txt b/Documentation/arm64/silicon-errata.txt
> index 10f2dddbf449..f5f93dca54b7 100644
> --- a/Documentation/arm64/silicon-errata.txt
> +++ b/Documentation/arm64/silicon-errata.txt
> @@ -62,6 +62,7 @@ stable kernels.
> | Cavium | ThunderX GICv3 | #23154 | CAVIUM_ERRATUM_23154 |
> | Cavium | ThunderX Core | #27456 | CAVIUM_ERRATUM_27456 |
> | Cavium | ThunderX SMMUv2 | #27704 | N/A |
> +| Cavium | ThunderX Core | #30115 | CAVIUM_ERRATUM_30115 |
> | | | | |
> | Freescale/NXP | LS2080A/LS1043A | A-008585 | FSL_ERRATUM_A008585 |
> | | | | |
> diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
> index 3dcd7ec69bca..0950b21e4d17 100644
> --- a/arch/arm64/Kconfig
> +++ b/arch/arm64/Kconfig
> @@ -480,6 +480,17 @@ config CAVIUM_ERRATUM_27456
>
> If unsure, say Y.
>
> +config CAVIUM_ERRATUM_30115
> + bool "Cavium erratum 30115: Guest may disable interrupts in host"
> + default y
> + help
> + On ThunderX T88 pass 1.x through 2.2, T81 pass 1.0 through
> + 1.2, and T83 Pass 1.0, KVM guest execution may disable
> + interrupts in host. Trapping GICv3 group-1 accesses sidesteps
> + the issue.
> +
> + If unsure, say Y.
> +
> config QCOM_FALKOR_ERRATUM_1003
> bool "Falkor E1003: Incorrect translation due to ASID change"
> default y
> diff --git a/arch/arm64/include/asm/cpucaps.h b/arch/arm64/include/asm/cpucaps.h
> index b3aab8a17868..8d2272c6822c 100644
> --- a/arch/arm64/include/asm/cpucaps.h
> +++ b/arch/arm64/include/asm/cpucaps.h
> @@ -38,7 +38,8 @@
> #define ARM64_WORKAROUND_REPEAT_TLBI 17
> #define ARM64_WORKAROUND_QCOM_FALKOR_E1003 18
> #define ARM64_WORKAROUND_858921 19
> +#define ARM64_WORKAROUND_CAVIUM_30115 20
>
> -#define ARM64_NCAPS 20
> +#define ARM64_NCAPS 21
>
> #endif /* __ASM_CPUCAPS_H */
> diff --git a/arch/arm64/kernel/cpu_errata.c b/arch/arm64/kernel/cpu_errata.c
> index 2ed2a7657711..0e27f86ee709 100644
> --- a/arch/arm64/kernel/cpu_errata.c
> +++ b/arch/arm64/kernel/cpu_errata.c
> @@ -133,6 +133,27 @@ const struct arm64_cpu_capabilities arm64_errata[] = {
> MIDR_RANGE(MIDR_THUNDERX_81XX, 0x00, 0x00),
> },
> #endif
> +#ifdef CONFIG_CAVIUM_ERRATUM_30115
> + {
> + /* Cavium ThunderX, T88 pass 1.x - 2.2 */
> + .desc = "Cavium erratum 30115",
> + .capability = ARM64_WORKAROUND_CAVIUM_30115,
> + MIDR_RANGE(MIDR_THUNDERX, 0x00,
> + (1 << MIDR_VARIANT_SHIFT) | 2),
> + },
> + {
> + /* Cavium ThunderX, T81 pass 1.0 - 1.2 */
> + .desc = "Cavium erratum 30115",
> + .capability = ARM64_WORKAROUND_CAVIUM_30115,
> + MIDR_RANGE(MIDR_THUNDERX_81XX, 0x00, 0x02),
> + },
> + {
> + /* Cavium ThunderX, T83 pass 1.0 */
> + .desc = "Cavium erratum 30115",
> + .capability = ARM64_WORKAROUND_CAVIUM_30115,
> + MIDR_RANGE(MIDR_THUNDERX_83XX, 0x00, 0x00),
> + },
> +#endif
> {
> .desc = "Mismatched cache line size",
> .capability = ARM64_MISMATCHED_CACHE_LINE_SIZE,
> diff --git a/virt/kvm/arm/vgic/vgic-v3.c b/virt/kvm/arm/vgic/vgic-v3.c
> index 7c82c586d44a..445e86c8b00c 100644
> --- a/virt/kvm/arm/vgic/vgic-v3.c
> +++ b/virt/kvm/arm/vgic/vgic-v3.c
> @@ -390,6 +390,13 @@ int vgic_v3_probe(const struct gic_kvm_info *info)
> if (kvm_vgic_global_state.vcpu_base == 0)
> kvm_info("disabling GICv2 emulation\n");
>
> +#ifdef CONFIG_ARM64
> + if (cpus_have_const_cap(ARM64_WORKAROUND_CAVIUM_30115)) {
> + group0_trap = true;
> + group1_trap = true;
> + }
> +#endif
> +
> if (group0_trap || group1_trap) {
> kvm_info("GICv3 sysreg trapping enabled (reduced performance)\n");
> static_branch_enable(&vgic_v3_cpuif_trap);
>