Re: [Qemu-devel] [PATCH v1 05/10] target-arm: Add VTTBR_EL2

[Peter Maydell]

On 3 September 2015 at 21:14, Edgar E. Iglesias
<address@hidden> wrote:
> From: "Edgar E. Iglesias" <address@hidden>
>
> Signed-off-by: Edgar E. Iglesias <address@hidden>
> ---
>  target-arm/cpu.h    |  1 +
>  target-arm/helper.c | 34 ++++++++++++++++++++++++++++++++--
>  2 files changed, 33 insertions(+), 2 deletions(-)
>
> diff --git a/target-arm/cpu.h b/target-arm/cpu.h
> index ba22e12..0ebdaf7 100644
> --- a/target-arm/cpu.h
> +++ b/target-arm/cpu.h
> @@ -221,6 +221,7 @@ typedef struct CPUARMState {
>              };
>              uint64_t ttbr1_el[4];
>          };
> +        uint64_t vttbr_el2; /* Virtualization Translation Table Base.  */
>          /* MMU translation table base control. */
>          TCR tcr_el[4];
>          TCR vtcr_el2; /* Virtualization Translation Control.  */
> diff --git a/target-arm/helper.c b/target-arm/helper.c
> index c82aa1d..ec19e68 100644
> --- a/target-arm/helper.c
> +++ b/target-arm/helper.c
> @@ -2200,6 +2200,19 @@ static void vmsa_ttbr_write(CPUARMState *env, const 
> ARMCPRegInfo *ri,
>      raw_write(env, ri, value);
>  }
>
> +static void vttbr_write(CPUARMState *env, const ARMCPRegInfo *ri,
> +                        uint64_t value)
> +{
> +    ARMCPU *cpu = arm_env_get_cpu(env);
> +    CPUState *cs = CPU(cpu);
> +
> +    if (raw_read(env, ri) != value) {
> +        tlb_flush_by_mmuidx(cs, ARMMMUIdx_S12NSE1, ARMMMUIdx_S12NSE0,
> +                            ARMMMUIdx_S2NS, -1);

We only need the TLB flush because this could change the VMID and
our TLB doesn't handle VMIDs, right? That could use a comment
(compare the remark about ASIDs in vmsa_ttbr_write()).

> +        raw_write(env, ri, value);
> +    }
> +}
> +
>  static const ARMCPRegInfo vmsa_pmsa_cp_reginfo[] = {
>      { .name = "DFSR", .cp = 15, .crn = 5, .crm = 0, .opc1 = 0, .opc2 = 0,
>        .access = PL1_RW, .type = ARM_CP_ALIAS,
> @@ -3131,6 +3144,14 @@ static const ARMCPRegInfo el3_no_el2_cp_reginfo[] = {
>        .opc0 = 3, .opc1 = 4, .crn = 2, .crm = 1, .opc2 = 2,
>        .access = PL2_RW, .accessfn = access_el3_aa32ns_aa64any,
>        .readfn = arm_cp_read_zero, .writefn = arm_cp_write_ignore },
> +    { .name = "VTTBR", .state = ARM_CP_STATE_AA32, .type = ARM_CP_64BIT,
> +      .cp = 15, .opc1 = 6, .crm = 2,
> +      .access = PL2_RW, .accessfn = access_el3_aa32ns_aa64any,
> +      .readfn = arm_cp_read_zero, .writefn = arm_cp_write_ignore },
> +    { .name = "VTTBR_EL2", .state = ARM_CP_STATE_AA64,
> +      .opc0 = 3, .opc1 = 4, .crn = 2, .crm = 1, .opc2 = 0,
> +      .access = PL2_RW, .accessfn = access_el3_aa32ns_aa64any,
> +      .readfn = arm_cp_read_zero, .writefn = arm_cp_write_ignore },

RAZ/WI registers not using ARM_CP_CONST again...

>      { .name = "SCTLR_EL2", .state = ARM_CP_STATE_BOTH,
>        .opc0 = 3, .opc1 = 4, .crn = 1, .crm = 0, .opc2 = 0,
>        .access = PL2_RW, .type = ARM_CP_CONST, .resetvalue = 0 },
> @@ -3271,6 +3292,16 @@ static const ARMCPRegInfo el2_cp_reginfo[] = {
>        .writefn = vmsa_tcr_el1_write,
>        .resetfn = vmsa_ttbcr_reset, .raw_writefn = raw_write,
>        .fieldoffset = offsetof(CPUARMState, cp15.vtcr_el2) },
> +    { .name = "VTTBR", .state = ARM_CP_STATE_AA32, .type = ARM_CP_64BIT,
> +      .cp = 15, .opc1 = 6, .crm = 2,
> +      .access = PL2_RW, .accessfn = access_el3_aa32ns_aa64any,
> +      .fieldoffset = offsetof(CPUARMState, cp15.vttbr_el2),
> +      .writefn = vttbr_write },
> +    { .name = "VTTBR_EL2", .state = ARM_CP_STATE_AA64,
> +      .opc0 = 3, .opc1 = 4, .crn = 2, .crm = 1, .opc2 = 0,
> +      .access = PL2_RW, .accessfn = access_el3_aa32ns_aa64any,
> +      .fieldoffset = offsetof(CPUARMState, cp15.vttbr_el2),
> +      .writefn = vttbr_write },
>      { .name = "SCTLR_EL2", .state = ARM_CP_STATE_BOTH,
>        .opc0 = 3, .opc1 = 4, .crn = 1, .crm = 0, .opc2 = 0,
>        .access = PL2_RW, .raw_writefn = raw_write, .writefn = sctlr_write,
> @@ -5770,8 +5801,7 @@ static inline uint64_t regime_ttbr(CPUARMState *env, 
> ARMMMUIdx mmu_idx,
>                                     int ttbrn)
>  {
>      if (mmu_idx == ARMMMUIdx_S2NS) {
> -        /* TODO: return VTTBR_EL2 */
> -        g_assert_not_reached();
> +        return env->cp15.vttbr_el2;
>      }
>      if (ttbrn == 0) {
>          return env->cp15.ttbr0_el[regime_el(env, mmu_idx)];
> --
> 1.9.1
>

thanks
-- PMM