On 04.10.20 2:00, Jan Kiszka wrote:
> From: Jan Kiszka <[email protected]>
>
> Array lookup is simpler, given this input-output mapping. Cover the
> 52-bit case as well at this chance. This also obsoletes a couple of
> PARANGE constants.
>
> Signed-off-by: Jan Kiszka <[email protected]>
> ---
> hypervisor/arch/arm64/include/asm/paging.h | 5 -----
> hypervisor/arch/arm64/paging.c | 19 +++----------------
> 2 files changed, 3 insertions(+), 21 deletions(-)
>
> diff --git a/hypervisor/arch/arm64/include/asm/paging.h
> b/hypervisor/arch/arm64/include/asm/paging.h
> index 67664efa..932dbb50 100644
> --- a/hypervisor/arch/arm64/include/asm/paging.h
> +++ b/hypervisor/arch/arm64/include/asm/paging.h
> @@ -101,11 +101,6 @@
> #define SL0_L02
> #define SL0_L11
> #define SL0_L20
> -#define PARANGE_32B0x0
> -#define PARANGE_36B0x1
> -#define PARANGE_40B0x2
> -#define PARANGE_42B0x3
> -#define PARANGE_44B0x4
> #define PARANGE_48B0x5
> #define TCR_RGN_NON_CACHEABLE0x0
> #define TCR_RGN_WB_WA0x1
> diff --git a/hypervisor/arch/arm64/paging.c b/hypervisor/arch/arm64/paging.c
> index db8314a6..cccce410 100644
> --- a/hypervisor/arch/arm64/paging.c
> +++ b/hypervisor/arch/arm64/paging.c
> @@ -26,6 +26,7 @@ unsigned int cpu_parange_encoded;
> */
> unsigned int get_cpu_parange(void)
> {
> +static const unsigned int pa_bits[] = { 32, 36, 40, 42, 44, 48, 52 };
Hi Jan,
I think it's safest and easiest to treat the 52-bit case as if it were
48-bit.
The 52-bit case is a bit trickier than the others in that it requires a
64KB translation granule. With a 4KB translation granule, the maximum
number of PA bits is 48; programming for 52-bit is treated as if it were
48-bit, so having this indicate that output addresses are 52-bit is a
bit misleading.
The real problem is that we set T0SZ such that the input address size is
the same as the output address size. When not using a 64KB translation
granule, programming a 52-bit input address size will result in
translation faults.
Chase
> unsigned int cpu;
>
> /* Larger than any possible value */
> @@ -42,20 +43,6 @@ unsigned int get_cpu_parange(void)
> (per_cpu(cpu)->id_aa64mmfr0 & 0xf) < cpu_parange_encoded)
> cpu_parange_encoded = per_cpu(cpu)->id_aa64mmfr0 & 0xf;
>
> -switch (cpu_parange_encoded) {
> -case PARANGE_32B:
> -return 32;
> -case PARANGE_36B:
> -return 36;
> -case PARANGE_40B:
> -return 40;
> -case PARANGE_42B:
> -return 42;
> -case PARANGE_44B:
> -return 44;
> -case PARANGE_48B:
> -return 48;
> -default:
> -return 0;
> -}
> +return cpu_parange_encoded < ARRAY_SIZE(pa_bits) ?
> +pa_bits[cpu_parange_encoded] : 0;
> }
> --
> 2.26.2
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