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

[Christoffer Dall]

On Thu, Oct 19, 2017 at 03:58:07PM +0100, James Morse wrote:
> From: Dongjiu Geng <gengdongjiu at 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 at 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 at arm.com>

Reviewed-by: Christoffer Dall <christoffer.dall at 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
>