On 08/12/15 12:47, Shannon Zhao wrote:
> From: Shannon Zhao <shannon.z...@linaro.org>
> 
> Add reset handler which gets host value of PMCEID0 or PMCEID1. Since
> write action to PMCEID0 or PMCEID1 is ignored, add a new case for this.
> 
> Signed-off-by: Shannon Zhao <shannon.z...@linaro.org>
> ---
>  arch/arm64/kvm/sys_regs.c | 29 +++++++++++++++++++++++++----
>  1 file changed, 25 insertions(+), 4 deletions(-)
> 
> diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
> index d81f7ac..1bcb2b7 100644
> --- a/arch/arm64/kvm/sys_regs.c
> +++ b/arch/arm64/kvm/sys_regs.c
> @@ -452,6 +452,19 @@ static void reset_pmcr(struct kvm_vcpu *vcpu, const 
> struct sys_reg_desc *r)
>       vcpu_sys_reg(vcpu, r->reg) = val;
>  }
>  
> +static void reset_pmceid(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
> +{
> +     u64 pmceid;
> +
> +     if (r->reg == PMCEID0_EL0)
> +             asm volatile("mrs %0, pmceid0_el0\n" : "=r" (pmceid));
> +     else
> +             /* PMCEID1_EL0 */
> +             asm volatile("mrs %0, pmceid1_el0\n" : "=r" (pmceid));
> +
> +     vcpu_sys_reg(vcpu, r->reg) = pmceid;
> +}
> +
>  /* PMU registers accessor. */
>  static bool access_pmu_regs(struct kvm_vcpu *vcpu,
>                           struct sys_reg_params *p,
> @@ -469,6 +482,9 @@ static bool access_pmu_regs(struct kvm_vcpu *vcpu,
>                       vcpu_sys_reg(vcpu, r->reg) = val;
>                       break;
>               }
> +             case PMCEID0_EL0:
> +             case PMCEID1_EL0:
> +                     return ignore_write(vcpu, p);
>               default:
>                       vcpu_sys_reg(vcpu, r->reg) = p->regval;
>                       break;
> @@ -693,10 +709,10 @@ static const struct sys_reg_desc sys_reg_descs[] = {
>         access_pmu_regs, reset_unknown, PMSELR_EL0 },
>       /* PMCEID0_EL0 */
>       { Op0(0b11), Op1(0b011), CRn(0b1001), CRm(0b1100), Op2(0b110),
> -       trap_raz_wi },
> +       access_pmu_regs, reset_pmceid, PMCEID0_EL0 },
>       /* PMCEID1_EL0 */
>       { Op0(0b11), Op1(0b011), CRn(0b1001), CRm(0b1100), Op2(0b111),
> -       trap_raz_wi },
> +       access_pmu_regs, reset_pmceid, PMCEID1_EL0 },
>       /* PMCCNTR_EL0 */
>       { Op0(0b11), Op1(0b011), CRn(0b1001), CRm(0b1101), Op2(0b000),
>         trap_raz_wi },
> @@ -926,6 +942,9 @@ static bool access_pmu_cp15_regs(struct kvm_vcpu *vcpu,
>                       vcpu_cp15(vcpu, r->reg) = val;
>                       break;
>               }
> +             case c9_PMCEID0:
> +             case c9_PMCEID1:
> +                     return ignore_write(vcpu, p);
>               default:
>                       vcpu_cp15(vcpu, r->reg) = p->regval;
>                       break;
> @@ -983,8 +1002,10 @@ static const struct sys_reg_desc cp15_regs[] = {
>       { Op1( 0), CRn( 9), CRm(12), Op2( 3), trap_raz_wi },
>       { Op1( 0), CRn( 9), CRm(12), Op2( 5), access_pmu_cp15_regs,
>         NULL, c9_PMSELR },
> -     { Op1( 0), CRn( 9), CRm(12), Op2( 6), trap_raz_wi },
> -     { Op1( 0), CRn( 9), CRm(12), Op2( 7), trap_raz_wi },
> +     { Op1( 0), CRn( 9), CRm(12), Op2( 6), access_pmu_cp15_regs,
> +       NULL, c9_PMCEID0 },
> +     { Op1( 0), CRn( 9), CRm(12), Op2( 7), access_pmu_cp15_regs,
> +       NULL, c9_PMCEID1 },
>       { Op1( 0), CRn( 9), CRm(13), Op2( 0), trap_raz_wi },
>       { Op1( 0), CRn( 9), CRm(13), Op2( 1), trap_raz_wi },
>       { Op1( 0), CRn( 9), CRm(13), Op2( 2), trap_raz_wi },
> 

That's a lot of infrastructure for something that is essentially a
constant that doesn't need to be stored in the sysreg array.
I suggest you drop the constants for PMCEID{0,1}_EL0 and
c9_PMCEID{0,1}, and turn the code into something like this:

diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index 251d517..09c38d0 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -453,17 +453,22 @@ static void reset_pmcr(struct kvm_vcpu *vcpu, const 
struct sys_reg_desc *r)
        vcpu_sys_reg(vcpu, r->reg) = val;
 }
 
-static void reset_pmceid(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
+static bool access_pmceid(struct kvm_vcpu *vcpu,
+                         struct sys_reg_params *p,
+                         const struct sys_reg_desc *r)
 {
        u64 pmceid;
 
-       if (r->reg == PMCEID0_EL0)
+       if (p->is_write)
+               return ignore_write(vcpu, p);
+
+       if (!(p->Op2 & 1))
                asm volatile("mrs %0, pmceid0_el0\n" : "=r" (pmceid));
        else
-               /* PMCEID1_EL0 */
                asm volatile("mrs %0, pmceid1_el0\n" : "=r" (pmceid));
 
-       vcpu_sys_reg(vcpu, r->reg) = pmceid;
+       p->regval = pmceid;
+       return true;
 }
 
 static bool pmu_counter_idx_valid(u64 pmcr, u64 idx)
@@ -624,9 +629,6 @@ static bool access_pmu_regs(struct kvm_vcpu *vcpu,
                        kvm_pmu_handle_pmcr(vcpu, val);
                        break;
                }
-               case PMCEID0_EL0:
-               case PMCEID1_EL0:
-                       return ignore_write(vcpu, p);
                default:
                        vcpu_sys_reg(vcpu, r->reg) = p->regval;
                        break;
@@ -873,10 +875,10 @@ static const struct sys_reg_desc sys_reg_descs[] = {
          access_pmu_regs, reset_unknown, PMSELR_EL0 },
        /* PMCEID0_EL0 */
        { Op0(0b11), Op1(0b011), CRn(0b1001), CRm(0b1100), Op2(0b110),
-         access_pmu_regs, reset_pmceid, PMCEID0_EL0 },
+         access_pmceid },
        /* PMCEID1_EL0 */
        { Op0(0b11), Op1(0b011), CRn(0b1001), CRm(0b1100), Op2(0b111),
-         access_pmu_regs, reset_pmceid, PMCEID1_EL0 },
+         access_pmceid },
        /* PMCCNTR_EL0 */
        { Op0(0b11), Op1(0b011), CRn(0b1001), CRm(0b1101), Op2(0b000),
          access_pmu_regs, reset_unknown, PMCCNTR_EL0 },
@@ -1223,9 +1225,6 @@ static bool access_pmu_cp15_regs(struct kvm_vcpu *vcpu,
                        kvm_pmu_handle_pmcr(vcpu, val);
                        break;
                }
-               case c9_PMCEID0:
-               case c9_PMCEID1:
-                       return ignore_write(vcpu, p);
                default:
                        vcpu_cp15(vcpu, r->reg) = p->regval;
                        break;
@@ -1310,10 +1309,8 @@ static const struct sys_reg_desc cp15_regs[] = {
          NULL, c9_PMSWINC },
        { Op1( 0), CRn( 9), CRm(12), Op2( 5), access_pmu_cp15_regs,
          NULL, c9_PMSELR },
-       { Op1( 0), CRn( 9), CRm(12), Op2( 6), access_pmu_cp15_regs,
-         NULL, c9_PMCEID0 },
-       { Op1( 0), CRn( 9), CRm(12), Op2( 7), access_pmu_cp15_regs,
-         NULL, c9_PMCEID1 },
+       { Op1( 0), CRn( 9), CRm(12), Op2( 6), access_pmceid },
+       { Op1( 0), CRn( 9), CRm(12), Op2( 7), access_pmceid },
        { Op1( 0), CRn( 9), CRm(13), Op2( 0), access_pmu_cp15_regs,
          NULL, c9_PMCCNTR },
        { Op1( 0), CRn( 9), CRm(13), Op2( 1), access_pmu_pmxevtyper },

All we need is an accessor, nothing else.

Thanks,

        M.
-- 
Jazz is not dead. It just smells funny...
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