From: "Cédric Le Goater" <clg@kaod.org>
To: David Gibson <david@gibson.dropbear.id.au>,
qemu-devel@nongnu.org, groug@kaod.org, philmd@redhat.com
Cc: aik@ozlabs.ru, Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>,
qemu-ppc@nongnu.org, lvivier@redhat.com, paulus@samba.org
Subject: Re: [PATCH v2 08/10] target/ppc: Streamline calculation of RMA limit from LPCR[RMLS]
Date: Tue, 7 Jan 2020 14:43:15 +0100 [thread overview]
Message-ID: <a5f22049-2c99-043e-53a9-93c8947f0b02@kaod.org> (raw)
In-Reply-To: <20200107044827.471355-9-david@gibson.dropbear.id.au>
On 1/7/20 5:48 AM, David Gibson wrote:
> Currently we use a big switch statement in ppc_hash64_update_rmls() to work
> out what the right RMA limit is based on the LPCR[RMLS] field. There's no
> formula for this - it's just an arbitrary mapping defined by the existing
> CPU implementations - but we can make it a bit more readable by using a
> lookup table rather than a switch. In addition we can use the MiB/GiB
> symbols to make it a bit clearer.
>
> While there we add a bit of clarity and rationale to the comment about
> what happens if the LPCR[RMLS] doesn't contain a valid value.
>
> Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Reviewed-by: Cédric Le Goater <clg@kaod.org>
> ---
> target/ppc/mmu-hash64.c | 71 ++++++++++++++++++++---------------------
> 1 file changed, 35 insertions(+), 36 deletions(-)
>
> diff --git a/target/ppc/mmu-hash64.c b/target/ppc/mmu-hash64.c
> index 127b7250ae..bb9ebeaf48 100644
> --- a/target/ppc/mmu-hash64.c
> +++ b/target/ppc/mmu-hash64.c
> @@ -18,6 +18,7 @@
> * License along with this library; if not, see <http://www.gnu.org/licenses/>.
> */
> #include "qemu/osdep.h"
> +#include "qemu/units.h"
> #include "cpu.h"
> #include "exec/exec-all.h"
> #include "exec/helper-proto.h"
> @@ -755,6 +756,39 @@ static void ppc_hash64_set_c(PowerPCCPU *cpu, hwaddr ptex, uint64_t pte1)
> stb_phys(CPU(cpu)->as, base + offset, (pte1 & 0xff) | 0x80);
> }
>
> +static target_ulong rmls_limit(PowerPCCPU *cpu)
> +{
> + CPUPPCState *env = &cpu->env;
> + /*
> + * This is the full 4 bits encoding of POWER8. Previous
> + * CPUs only support a subset of these but the filtering
> + * is done when writing LPCR
> + */
> + const target_ulong rma_sizes[] = {
> + [0] = 0,
> + [1] = 16 * GiB,
> + [2] = 1 * GiB,
> + [3] = 64 * MiB,
> + [4] = 256 * MiB,
> + [5] = 0,
> + [6] = 0,
> + [7] = 128 * MiB,
> + [8] = 32 * MiB,
> + };
> + target_ulong rmls = (env->spr[SPR_LPCR] & LPCR_RMLS) >> LPCR_RMLS_SHIFT;
> +
> + if (rmls < ARRAY_SIZE(rma_sizes)) {
> + return rma_sizes[rmls];
> + } else {
> + /*
> + * Bad value, so the OS has shot itself in the foot. Return a
> + * 0-sized RMA which we expect to trigger an immediate DSI or
> + * ISI
> + */
> + return 0;
> + }
> +}
> +
> int ppc_hash64_handle_mmu_fault(PowerPCCPU *cpu, vaddr eaddr,
> int rwx, int mmu_idx)
> {
> @@ -1004,41 +1038,6 @@ void ppc_hash64_tlb_flush_hpte(PowerPCCPU *cpu, target_ulong ptex,
> cpu->env.tlb_need_flush = TLB_NEED_GLOBAL_FLUSH | TLB_NEED_LOCAL_FLUSH;
> }
>
> -static void ppc_hash64_update_rmls(PowerPCCPU *cpu)
> -{
> - CPUPPCState *env = &cpu->env;
> - uint64_t lpcr = env->spr[SPR_LPCR];
> -
> - /*
> - * This is the full 4 bits encoding of POWER8. Previous
> - * CPUs only support a subset of these but the filtering
> - * is done when writing LPCR
> - */
> - switch ((lpcr & LPCR_RMLS) >> LPCR_RMLS_SHIFT) {
> - case 0x8: /* 32MB */
> - env->rmls = 0x2000000ull;
> - break;
> - case 0x3: /* 64MB */
> - env->rmls = 0x4000000ull;
> - break;
> - case 0x7: /* 128MB */
> - env->rmls = 0x8000000ull;
> - break;
> - case 0x4: /* 256MB */
> - env->rmls = 0x10000000ull;
> - break;
> - case 0x2: /* 1GB */
> - env->rmls = 0x40000000ull;
> - break;
> - case 0x1: /* 16GB */
> - env->rmls = 0x400000000ull;
> - break;
> - default:
> - /* What to do here ??? */
> - env->rmls = 0;
> - }
> -}
> -
> static void ppc_hash64_update_vrma(PowerPCCPU *cpu)
> {
> CPUPPCState *env = &cpu->env;
> @@ -1097,7 +1096,7 @@ void ppc_store_lpcr(PowerPCCPU *cpu, target_ulong val)
> CPUPPCState *env = &cpu->env;
>
> env->spr[SPR_LPCR] = val & pcc->lpcr_mask;
> - ppc_hash64_update_rmls(cpu);
> + env->rmls = rmls_limit(cpu);
> ppc_hash64_update_vrma(cpu);
> }
>
>
next prev parent reply other threads:[~2020-01-07 14:18 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-07 4:48 [PATCH v2 00/10] target/ppc: Correct some errors with real mode handling David Gibson
2020-01-07 4:48 ` [PATCH v2 01/10] ppc: Drop PPC_EMULATE_32BITS_HYPV stub David Gibson
2020-01-07 12:52 ` Cédric Le Goater
2020-01-07 17:05 ` Greg Kurz
2020-01-07 4:48 ` [PATCH v2 02/10] ppc: Remove stub of PPC970 HID4 implementation David Gibson
2020-01-07 12:51 ` Cédric Le Goater
2020-01-07 17:32 ` Greg Kurz
2020-01-07 17:36 ` Greg Kurz
2020-01-07 18:05 ` BALATON Zoltan
2020-01-08 1:09 ` David Gibson
2020-01-08 8:29 ` Thomas Huth
2020-01-08 1:08 ` David Gibson
2020-01-08 8:11 ` Greg Kurz
2020-01-08 2:17 ` Paul Mackerras
2020-01-08 13:35 ` Greg Kurz
2020-01-07 4:48 ` [PATCH v2 03/10] target/ppc: Correct handling of real mode accesses with vhyp on hash MMU David Gibson
2020-01-14 10:22 ` Cédric Le Goater
2020-01-07 4:48 ` [PATCH v2 04/10] target/ppc: Introduce ppc_hash64_use_vrma() helper David Gibson
2020-01-07 13:24 ` Cédric Le Goater
2020-01-07 4:48 ` [PATCH v2 05/10] spapr, ppc: Remove VPM0/RMLS hacks for POWER9 David Gibson
2020-01-07 14:35 ` Cédric Le Goater
2020-01-09 7:33 ` Alexey Kardashevskiy
2020-01-13 3:38 ` David Gibson
2020-01-07 4:48 ` [PATCH v2 06/10] target/ppc: Remove RMOR register from POWER9 & POWER10 David Gibson
2020-01-07 13:39 ` Cédric Le Goater
2020-01-07 4:48 ` [PATCH v2 07/10] target/ppc: Use class fields to simplify LPCR masking David Gibson
2020-01-07 13:41 ` Cédric Le Goater
2020-01-07 4:48 ` [PATCH v2 08/10] target/ppc: Streamline calculation of RMA limit from LPCR[RMLS] David Gibson
2020-01-07 13:43 ` Cédric Le Goater [this message]
2020-01-07 4:48 ` [PATCH v2 09/10] target/ppc: Correct RMLS table David Gibson
2020-01-07 14:21 ` Cédric Le Goater
2020-01-08 1:06 ` David Gibson
2020-01-08 8:29 ` Cédric Le Goater
2020-01-09 7:46 ` Alexey Kardashevskiy
2020-01-13 3:46 ` David Gibson
2020-01-08 8:28 ` Cédric Le Goater
2020-01-07 4:48 ` [PATCH v2 10/10] target/ppc: Only calculate RMLS derived RMA limit on demand David Gibson
2020-01-08 8:31 ` Cédric Le Goater
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