From: Nicholas Piggin <npiggin@gmail•com>
To: Bharata B Rao <bharata@linux•ibm.com>, Qian Cai <cai@lca•pw>
Cc: aneesh.kumar@linux•ibm.com, linux-kernel@vger•kernel.org,
linux-next@vger•kernel.org, linuxppc-dev@lists•ozlabs.org,
mpe@ellerman•id.au, sfr@canb•auug.org.au
Subject: Re: [PATCH v3 0/3] Off-load TLB invalidations to host for !GTSE
Date: Fri, 17 Jul 2020 12:44:00 +1000 [thread overview]
Message-ID: <1594953143.b8px5ir35m.astroid@bobo.none> (raw)
In-Reply-To: <1594950229.jn9ipe6td1.astroid@bobo.none>
Excerpts from Nicholas Piggin's message of July 17, 2020 12:08 pm:
> Excerpts from Qian Cai's message of July 17, 2020 3:27 am:
>> On Fri, Jul 03, 2020 at 11:06:05AM +0530, Bharata B Rao wrote:
>>> Hypervisor may choose not to enable Guest Translation Shootdown Enable
>>> (GTSE) option for the guest. When GTSE isn't ON, the guest OS isn't
>>> permitted to use instructions like tblie and tlbsync directly, but is
>>> expected to make hypervisor calls to get the TLB flushed.
>>>
>>> This series enables the TLB flush routines in the radix code to
>>> off-load TLB flushing to hypervisor via the newly proposed hcall
>>> H_RPT_INVALIDATE.
>>>
>>> To easily check the availability of GTSE, it is made an MMU feature.
>>> The OV5 handling and H_REGISTER_PROC_TBL hcall are changed to
>>> handle GTSE as an optionally available feature and to not assume GTSE
>>> when radix support is available.
>>>
>>> The actual hcall implementation for KVM isn't included in this
>>> patchset and will be posted separately.
>>>
>>> Changes in v3
>>> =============
>>> - Fixed a bug in the hcall wrapper code where we were missing setting
>>> H_RPTI_TYPE_NESTED while retrying the failed flush request with
>>> a full flush for the nested case.
>>> - s/psize_to_h_rpti/psize_to_rpti_pgsize
>>>
>>> v2: https://lore.kernel.org/linuxppc-dev/20200626131000.5207-1-bharata@linux.ibm.com/T/#t
>>>
>>> Bharata B Rao (2):
>>> powerpc/mm: Enable radix GTSE only if supported.
>>> powerpc/pseries: H_REGISTER_PROC_TBL should ask for GTSE only if
>>> enabled
>>>
>>> Nicholas Piggin (1):
>>> powerpc/mm/book3s64/radix: Off-load TLB invalidations to host when
>>> !GTSE
>>
>> Reverting the whole series fixed random memory corruptions during boot on
>> POWER9 PowerNV systems below.
>
> If I s/mmu_has_feature(MMU_FTR_GTSE)/(1)/g in radix_tlb.c, then the .o
> disasm is the same as reverting my patch.
>
> Feature bits not being set right? PowerNV should be pretty simple, seems
> to do the same as FTR_TYPE_RADIX.
Might need this fix
---
diff --git a/arch/powerpc/kernel/prom.c b/arch/powerpc/kernel/prom.c
index 9cc49f265c86..54c9bcea9d4e 100644
--- a/arch/powerpc/kernel/prom.c
+++ b/arch/powerpc/kernel/prom.c
@@ -163,7 +163,7 @@ static struct ibm_pa_feature {
{ .pabyte = 0, .pabit = 6, .cpu_features = CPU_FTR_NOEXECUTE },
{ .pabyte = 1, .pabit = 2, .mmu_features = MMU_FTR_CI_LARGE_PAGE },
#ifdef CONFIG_PPC_RADIX_MMU
- { .pabyte = 40, .pabit = 0, .mmu_features = MMU_FTR_TYPE_RADIX },
+ { .pabyte = 40, .pabit = 0, .mmu_features = (MMU_FTR_TYPE_RADIX | MMU_FTR_GTSE) },
#endif
{ .pabyte = 1, .pabit = 1, .invert = 1, .cpu_features = CPU_FTR_NODSISRALIGN },
{ .pabyte = 5, .pabit = 0, .cpu_features = CPU_FTR_REAL_LE,
next prev parent reply other threads:[~2020-07-17 2:44 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20200703053608.12884-1-bharata@linux.ibm.com>
2020-07-16 17:27 ` [PATCH v3 0/3] Off-load TLB invalidations to host for !GTSE Qian Cai
2020-07-16 23:09 ` Stephen Rothwell
2020-07-17 2:08 ` Nicholas Piggin
2020-07-17 2:44 ` Nicholas Piggin [this message]
2020-07-17 4:28 ` Bharata B Rao
2020-07-18 12:40 ` Michael Ellerman
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