Re: [PATCH v4 21/21] KVM: arm64: Trap RAS error registers and set HCR_EL2's TERR & TEA

Christoffer Dall
2017-10-31T06:31:16Z

On Thu, Oct 19, 2017 at 03:58:07PM +0100, James Morse wrote:
> From: Dongjiu Geng <gengdongjiu@huawei.com>
>
> ARMv8.2 adds a new bit HCR_EL2.TEA which routes synchronous external
> aborts to EL2, and adds a trap control bit HCR_EL2.TERR which traps
> all Non-secure EL1&0 error record accesses to EL2.
>
> This patch enables the two bits for the guest OS, guaranteeing that
> KVM takes external aborts and traps attempts to access the physical
> error registers.
>
> ERRIDR_EL1 advertises the number of error records, we return
> zero meaning we can treat all the other registers as RAZ/WI too.
>
> Signed-off-by: Dongjiu Geng <gengdongjiu@huawei.com>
> [removed specific emulation, use trap_raz_wi() directly for everything,
> rephrased parts of the commit message]
> Signed-off-by: James Morse <james.morse@arm.com>

Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>

> ---
> arch/arm64/include/asm/kvm_arm.h | 2 ++
> arch/arm64/include/asm/kvm_emulate.h | 7 +++++++
> arch/arm64/include/asm/sysreg.h | 10 ++++++++++
> arch/arm64/kvm/sys_regs.c | 10 ++++++++++
> 4 files changed, 29 insertions(+)
>
> diff --git a/arch/arm64/include/asm/kvm_arm.h b/arch/arm64/include/asm/kvm_arm.h
> index 61d694c2eae5..1188272003c4 100644
> --- a/arch/arm64/include/asm/kvm_arm.h
> +++ b/arch/arm64/include/asm/kvm_arm.h
> @@ -23,6 +23,8 @@
> #include <asm/types.h>
>
> /* Hyp Configuration Register (HCR) bits */
> +#define HCR_TEA (UL(1) << 37)
> +#define HCR_TERR (UL(1) << 36)
> #define HCR_E2H (UL(1) << 34)
> #define HCR_ID (UL(1) << 33)
> #define HCR_CD (UL(1) << 32)
> diff --git a/arch/arm64/include/asm/kvm_emulate.h b/arch/arm64/include/asm/kvm_emulate.h
> index 8274d16df3cd..2cd666a9d47e 100644
> --- a/arch/arm64/include/asm/kvm_emulate.h
> +++ b/arch/arm64/include/asm/kvm_emulate.h
> @@ -47,6 +47,13 @@ static inline void vcpu_reset_hcr(struct kvm_vcpu *vcpu)
> vcpu->arch.hcr_el2 = HCR_GUEST_FLAGS;
> if (is_kernel_in_hyp_mode())
> vcpu->arch.hcr_el2 |= HCR_E2H;
> + if (cpus_have_const_cap(ARM64_HAS_RAS_EXTN)) {
> + /* route synchronous external abort exceptions to EL2 */
> + vcpu->arch.hcr_el2 |= HCR_TEA;
> + /* trap error record accesses */
> + vcpu->arch.hcr_el2 |= HCR_TERR;
> + }
> +
> if (test_bit(KVM_ARM_VCPU_EL1_32BIT, vcpu->arch.features))
> vcpu->arch.hcr_el2 &= ~HCR_RW;
> }
> diff --git a/arch/arm64/include/asm/sysreg.h b/arch/arm64/include/asm/sysreg.h
> index 1b8b9012234d..0d3c5c7bb425 100644
> --- a/arch/arm64/include/asm/sysreg.h
> +++ b/arch/arm64/include/asm/sysreg.h
> @@ -169,6 +169,16 @@
> #define SYS_AFSR0_EL1 sys_reg(3, 0, 5, 1, 0)
> #define SYS_AFSR1_EL1 sys_reg(3, 0, 5, 1, 1)
> #define SYS_ESR_EL1 sys_reg(3, 0, 5, 2, 0)
> +
> +#define SYS_ERRIDR_EL1 sys_reg(3, 0, 5, 3, 0)
> +#define SYS_ERRSELR_EL1 sys_reg(3, 0, 5, 3, 1)
> +#define SYS_ERXFR_EL1 sys_reg(3, 0, 5, 4, 0)
> +#define SYS_ERXCTLR_EL1 sys_reg(3, 0, 5, 4, 1)
> +#define SYS_ERXSTATUS_EL1 sys_reg(3, 0, 5, 4, 2)
> +#define SYS_ERXADDR_EL1 sys_reg(3, 0, 5, 4, 3)
> +#define SYS_ERXMISC0_EL1 sys_reg(3, 0, 5, 5, 0)
> +#define SYS_ERXMISC1_EL1 sys_reg(3, 0, 5, 5, 1)
> +
> #define SYS_FAR_EL1 sys_reg(3, 0, 6, 0, 0)
> #define SYS_PAR_EL1 sys_reg(3, 0, 7, 4, 0)
>
> diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
> index 713275b501ce..2b3b16bf5275 100644
> --- a/arch/arm64/kvm/sys_regs.c
> +++ b/arch/arm64/kvm/sys_regs.c
> @@ -953,6 +953,16 @@ static const struct sys_reg_desc sys_reg_descs[] = {
> { SYS_DESC(SYS_AFSR0_EL1), access_vm_reg, reset_unknown, AFSR0_EL1 },
> { SYS_DESC(SYS_AFSR1_EL1), access_vm_reg, reset_unknown, AFSR1_EL1 },
> { SYS_DESC(SYS_ESR_EL1), access_vm_reg, reset_unknown, ESR_EL1 },
> +
> + { SYS_DESC(SYS_ERRIDR_EL1), trap_raz_wi },
> + { SYS_DESC(SYS_ERRSELR_EL1), trap_raz_wi },
> + { SYS_DESC(SYS_ERXFR_EL1), trap_raz_wi },
> + { SYS_DESC(SYS_ERXCTLR_EL1), trap_raz_wi },
> + { SYS_DESC(SYS_ERXSTATUS_EL1), trap_raz_wi },
> + { SYS_DESC(SYS_ERXADDR_EL1), trap_raz_wi },
> + { SYS_DESC(SYS_ERXMISC0_EL1), trap_raz_wi },
> + { SYS_DESC(SYS_ERXMISC1_EL1), trap_raz_wi },
> +
> { SYS_DESC(SYS_FAR_EL1), access_vm_reg, reset_unknown, FAR_EL1 },
> { SYS_DESC(SYS_PAR_EL1), NULL, reset_unknown, PAR_EL1 },
>
> --
> 2.13.3
>