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Re: [Qemu-ppc] [PATCH 2/2] ppc: Allow 64kiB pages for POWER8 in TCG
From: |
Benjamin Herrenschmidt |
Subject: |
Re: [Qemu-ppc] [PATCH 2/2] ppc: Allow 64kiB pages for POWER8 in TCG |
Date: |
Mon, 21 Dec 2015 13:49:38 +1100 |
On Mon, 2015-12-21 at 13:41 +1100, David Gibson wrote:
> Now that the spapr code has been extended to support 64kiB pages, we can
> allow guests to use 64kiB pages on an emulated POWER8 by adding it to the
> "segment_page_sizes" structure which is advertised via the device tree.
>
> For now we just add support for 64kiB pages in 64kiB page segments. Real
> POWER8 also supports 64kiB pages in 4kiB page segments, but that will
> require more work to implement.
>
> Real POWER7s (and maybe some other CPU models) also support 64kiB pages,
> however, I don't want to add support there without double checking if they
> use the same HPTE and SLB encodings (in principle these are implementation
> dependent).
Don't I have a patch for that in my series already ? IIRC, I had
another fix somewhere...
https://github.com/ozbenh/qemu/commit/6c9dc80db82ed87d5ee77852930348232
f5f9db2
Cheers,
Ben.
> Signed-off-by: David Gibson <address@hidden>
> ---
> target-ppc/translate_init.c | 17 +++++++++++++++++
> 1 file changed, 17 insertions(+)
>
> diff --git a/target-ppc/translate_init.c b/target-ppc/translate_init.c
> index e88dc7f..ae5a269 100644
> --- a/target-ppc/translate_init.c
> +++ b/target-ppc/translate_init.c
> @@ -8200,6 +8200,22 @@ POWERPC_FAMILY(POWER8)(ObjectClass *oc, void *data)
> {
> DeviceClass *dc = DEVICE_CLASS(oc);
> PowerPCCPUClass *pcc = POWERPC_CPU_CLASS(oc);
> + static const struct ppc_segment_page_sizes POWER8_sps = {
> + .sps = {
> + { .page_shift = 12, /* 4K */
> + .slb_enc = 0,
> + .enc = { { .page_shift = 12, .pte_enc = 0 } }
> + },
> + { .page_shift = 16, /* 64K */
> + .slb_enc = 0x110,
> + .enc = { { .page_shift = 16, .pte_enc = 0x1 } }
> + },
> + { .page_shift = 24, /* 16M */
> + .slb_enc = 0x100,
> + .enc = { { .page_shift = 24, .pte_enc = 0 } }
> + },
> + }
> + };
>
> dc->fw_name = "PowerPC,POWER8";
> dc->desc = "POWER8";
> @@ -8258,6 +8274,7 @@ POWERPC_FAMILY(POWER8)(ObjectClass *oc, void *data)
> pcc->l1_dcache_size = 0x8000;
> pcc->l1_icache_size = 0x8000;
> pcc->interrupts_big_endian = ppc_cpu_interrupts_big_endian_lpcr;
> + pcc->sps = &POWER8_sps;
> }
> #endif /* defined (TARGET_PPC64) */
>