On Thu, Sep 17, 2020 at 08:00:57PM +0800, Peng Liang wrote:
> To emulate the ID registers, we need a place to storage the values of
> the ID regsiters. Maybe putting them in sysreg file is a good idea.
>
> This commit has no functional changes but only code refactor. When
> initializing a vCPU, get the values of the ID registers from
> arm64_ftr_regs and storage them in sysreg file. And we just read
> the value from sysreg file when getting/setting the value of the ID
> regs.
>
> Signed-off-by: zhanghailiang <zhang.zhanghailiang@xxxxxxxxxx>
> Signed-off-by: Peng Liang <liangpeng10@xxxxxxxxxx>
> ---
> arch/arm64/include/asm/kvm_coproc.h | 2 ++
> arch/arm64/include/asm/kvm_host.h | 3 +++
> arch/arm64/kvm/arm.c | 2 ++
> arch/arm64/kvm/sys_regs.c | 33 +++++++++++++++++++++++++----
> 4 files changed, 36 insertions(+), 4 deletions(-)
>
> diff --git a/arch/arm64/include/asm/kvm_coproc.h b/arch/arm64/include/asm/kvm_coproc.h
> index d6bb40122fdb..76e8c3cb0662 100644
> --- a/arch/arm64/include/asm/kvm_coproc.h
> +++ b/arch/arm64/include/asm/kvm_coproc.h
> @@ -35,4 +35,6 @@ int kvm_arm_sys_reg_get_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *);
> int kvm_arm_sys_reg_set_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *);
> unsigned long kvm_arm_num_sys_reg_descs(struct kvm_vcpu *vcpu);
>
> +void kvm_arm_sys_reg_init(struct kvm_vcpu *vcpu);
> +
> #endif /* __ARM64_KVM_COPROC_H__ */
> diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
> index 905c2b87e05a..50152e364c4f 100644
> --- a/arch/arm64/include/asm/kvm_host.h
> +++ b/arch/arm64/include/asm/kvm_host.h
> @@ -184,6 +184,9 @@ enum vcpu_sysreg {
> CNTP_CVAL_EL0,
> CNTP_CTL_EL0,
>
> + ID_REG_BASE,
> + ID_REG_END = ID_REG_BASE + 55,
> +
> /* 32bit specific registers. Keep them at the end of the range */
> DACR32_EL2, /* Domain Access Control Register */
> IFSR32_EL2, /* Instruction Fault Status Register */
> diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
> index b588c3b5c2f0..6d961e192268 100644
> --- a/arch/arm64/kvm/arm.c
> +++ b/arch/arm64/kvm/arm.c
> @@ -274,6 +274,8 @@ int kvm_arch_vcpu_create(struct kvm_vcpu *vcpu)
> if (err)
> return err;
>
> + kvm_arm_sys_reg_init(vcpu);
> +
> return create_hyp_mappings(vcpu, vcpu + 1, PAGE_HYP);
> }
>
> diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
> index 077293b5115f..2b0fa8d5ac62 100644
> --- a/arch/arm64/kvm/sys_regs.c
> +++ b/arch/arm64/kvm/sys_regs.c
> @@ -1119,13 +1119,16 @@ static bool access_arch_timer(struct kvm_vcpu *vcpu,
> return true;
> }
>
> +#define ID_REG_INDEX(id) \
> + (ID_REG_BASE + (((sys_reg_CRm(id) - 1) << 3) | sys_reg_Op2(id)))
> +
> /* Read a sanitised cpufeature ID register by sys_reg_desc */
> -static u64 read_id_reg(const struct kvm_vcpu *vcpu,
> +static u64 read_id_reg(struct kvm_vcpu *vcpu,
> struct sys_reg_desc const *r, bool raz)
> {
> u32 id = sys_reg((u32)r->Op0, (u32)r->Op1,
> (u32)r->CRn, (u32)r->CRm, (u32)r->Op2);
> - u64 val = raz ? 0 : read_sanitised_ftr_reg(id);
> + u64 val = raz ? 0 : __vcpu_sys_reg(vcpu, ID_REG_INDEX(id));
>
> if (id == SYS_ID_AA64PFR0_EL1) {
> if (!vcpu_has_sve(vcpu))
> @@ -1265,7 +1268,7 @@ static int set_id_aa64zfr0_el1(struct kvm_vcpu *vcpu,
> * are stored, and for set_id_reg() we don't allow the effective value
> * to be changed.
> */
> -static int __get_id_reg(const struct kvm_vcpu *vcpu,
> +static int __get_id_reg(struct kvm_vcpu *vcpu,
> const struct sys_reg_desc *rd, void __user *uaddr,
> bool raz)
> {
> @@ -1275,7 +1278,7 @@ static int __get_id_reg(const struct kvm_vcpu *vcpu,
> return reg_to_user(uaddr, &val, id);
> }
>
> -static int __set_id_reg(const struct kvm_vcpu *vcpu,
> +static int __set_id_reg(struct kvm_vcpu *vcpu,
> const struct sys_reg_desc *rd, void __user *uaddr,
> bool raz)
> {
> @@ -2854,3 +2857,25 @@ void kvm_sys_reg_table_init(void)
> /* Clear all higher bits. */
> cache_levels &= (1 << (i*3))-1;
> }
> +
> +static int get_cpu_ftr(u32 id, u64 val, void *argp)
'get' doesn't seem like the right verb here, but I don't think we need
this function anyway, since we don't need arm64_cpu_ftr_regs_traverse().
Just put the for-loop for arm64_cpu_ftr_regs_traverse() and this code
directly in kvm_arm_sys_reg_init().
> +{
> + struct kvm_vcpu *vcpu = argp;
> +
> + /*
> + * (Op0, Op1, CRn, CRm, Op2) of ID registers is (3, 0, 0, crm, op2),
> + * where 1<=crm<8, 0<=op2<8.
> + */
> + if (sys_reg_Op0(id) == 3 && sys_reg_Op1(id) == 0 &&
> + sys_reg_CRn(id) == 0 && sys_reg_CRm(id) > 0 &&
> + sys_reg_CRm(id) < 8) {
> + __vcpu_sys_reg(vcpu, ID_REG_INDEX(id)) = val;
> + }
> +
> + return 0;
> +}
> +
> +void kvm_arm_sys_reg_init(struct kvm_vcpu *vcpu)
> +{
> + arm64_cpu_ftr_regs_traverse(get_cpu_ftr, vcpu);
> +}
> --
> 2.26.2
>
Besides the pointless functions, this patch looks fine to me.
Thanks,
drew
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