From: Andrew Cooper <andrew.cooper3@citrix.com>
To: "Ahmed S. Darwish" <darwi@linutronix.de>,
Borislav Petkov <bp@alien8.de>, Ingo Molnar <mingo@redhat.com>,
Dave Hansen <dave.hansen@linux.intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>,
John Ogness <john.ogness@linutronix.de>,
"H. Peter Anvin" <hpa@zytor.com>,
x86@kernel.org, x86-cpuid@lists.linux.dev,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v1 37/40] x86/cacheinfo: Extract out cache self-snoop checks
Date: Tue, 4 Mar 2025 10:38:33 +0000 [thread overview]
Message-ID: <01367a6b-8eeb-417e-9a66-e7a64d518319@citrix.com> (raw)
In-Reply-To: <20250304085152.51092-38-darwi@linutronix.de>
On 04/03/2025 8:51 am, Ahmed S. Darwish wrote:
> The logic of not doing a cache flush if the CPU declares cache self
> snooping support is repeated across the x86/cacheinfo code. Extract it
> into its own function.
>
> Signed-off-by: Ahmed S. Darwish <darwi@linutronix.de>
I know you're just refactoring code, but the SDM has basically reverted
this statement about it being safe to skip WBINVD based on SELFSNOOP.
It turns out not to be safe in cases where the underlying physical
memory changes from cacheable to unchangeable. By skipping the WBINVD
as part of changing the memory type, you end up with spurious writebacks
at a later point when the memory is expected to be UC. Apparently this
is a problem for CLX devices, hence the change in the SDM.
~Andrew
next prev parent reply other threads:[~2025-03-04 10:38 UTC|newest]
Thread overview: 78+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-03-04 8:51 [PATCH v1 00/40] x86: Leaf 0x2 and leaf 0x4 refactorings Ahmed S. Darwish
2025-03-04 8:51 ` [PATCH v1 01/40] x86/cacheinfo: Validate cpuid leaf 0x2 EDX output Ahmed S. Darwish
2025-03-04 9:37 ` [tip: x86/urgent] x86/cacheinfo: Validate CPUID " tip-bot2 for Ahmed S. Darwish
2025-03-04 8:51 ` [PATCH v1 02/40] x86/cpu: Validate cpuid " Ahmed S. Darwish
2025-03-04 9:37 ` [tip: x86/urgent] x86/cpu: Validate CPUID " tip-bot2 for Ahmed S. Darwish
2025-03-04 8:51 ` [PATCH v1 03/40] x86/cpu: Properly parse leaf 0x2 TLB descriptor 0x63 Ahmed S. Darwish
2025-03-04 9:37 ` [tip: x86/urgent] x86/cpu: Properly parse CPUID " tip-bot2 for Ahmed S. Darwish
2025-03-04 8:51 ` [PATCH v1 04/40] x86/cpuid: Include linux/build_bug.h Ahmed S. Darwish
2025-03-04 9:37 ` [tip: x86/cpu] x86/cpuid: Include <linux/build_bug.h> in <asm/cpuid.h> tip-bot2 for Ahmed S. Darwish
2025-03-04 10:26 ` tip-bot2 for Ahmed S. Darwish
2025-03-04 8:51 ` [PATCH v1 05/40] x86/cpu: Remove unnecessary headers and reorder the rest Ahmed S. Darwish
2025-03-04 9:14 ` Ingo Molnar
2025-03-04 9:28 ` Ahmed S. Darwish
2025-03-04 9:37 ` [tip: x86/cpu] " tip-bot2 for Ahmed S. Darwish
2025-03-04 10:26 ` tip-bot2 for Ahmed S. Darwish
2025-03-04 8:51 ` [PATCH v1 06/40] x86/cpu: Use max() for leaf 0x2 TLB descriptors parsing Ahmed S. Darwish
2025-03-04 9:37 ` [tip: x86/cpu] x86/cpu: Use max() for CPUID " tip-bot2 for Ahmed S. Darwish
2025-03-04 10:26 ` tip-bot2 for Ahmed S. Darwish
2025-03-04 8:51 ` [PATCH v1 07/40] x86/cpu: Simplify TLB entry count storage Ahmed S. Darwish
2025-03-04 9:37 ` [tip: x86/cpu] " tip-bot2 for Ahmed S. Darwish
2025-03-04 10:26 ` tip-bot2 for Ahmed S. Darwish
2025-03-04 8:51 ` [PATCH v1 08/40] x86/cpu: Get rid of smp_store_cpu_info() indirection Ahmed S. Darwish
2025-03-04 9:37 ` [tip: x86/cpu] x86/cpu: Get rid of the " tip-bot2 for Thomas Gleixner
2025-03-04 10:26 ` tip-bot2 for Thomas Gleixner
2025-03-04 8:51 ` [PATCH v1 09/40] x86/cpu: Remove unused TLB strings Ahmed S. Darwish
2025-03-04 9:37 ` [tip: x86/cpu] " tip-bot2 for Thomas Gleixner
2025-03-04 10:26 ` tip-bot2 for Thomas Gleixner
2025-03-04 8:51 ` [PATCH v1 10/40] x86/cpu: Remove leaf 0x2 parsing loop and add helpers Ahmed S. Darwish
2025-03-04 9:26 ` Ingo Molnar
2025-03-05 16:01 ` Ahmed S. Darwish
2025-03-04 8:51 ` [PATCH v1 11/40] x86/cacheinfo: Remove the P4 trace leftovers for real Ahmed S. Darwish
2025-03-04 9:47 ` [tip: x86/cpu] " tip-bot2 for Thomas Gleixner
2025-03-04 10:26 ` tip-bot2 for Thomas Gleixner
2025-03-04 8:51 ` [PATCH v1 12/40] x86/cacheinfo: Remove unnecessary headers and reorder the rest Ahmed S. Darwish
2025-03-04 9:47 ` [tip: x86/cpu] " tip-bot2 for Ahmed S. Darwish
2025-03-04 10:26 ` tip-bot2 for Ahmed S. Darwish
2025-03-04 8:51 ` [PATCH v1 13/40] x86/cacheinfo: Use cpuid leaf 0x2 parsing helpers Ahmed S. Darwish
2025-03-04 8:51 ` [PATCH v1 14/40] x86/cacheinfo: Refactor leaf 0x2 cache descriptor lookup Ahmed S. Darwish
2025-03-04 8:51 ` [PATCH v1 15/40] x86/cacheinfo: Properly name amd_cpuid4()'s first parameter Ahmed S. Darwish
2025-03-04 8:51 ` [PATCH v1 16/40] x86/cacheinfo: Use proper name for cacheinfo instances Ahmed S. Darwish
2025-03-04 8:51 ` [PATCH v1 17/40] x86/cacheinfo: Constify _cpuid4_info_regs instances Ahmed S. Darwish
2025-03-04 8:51 ` [PATCH v1 18/40] x86/cacheinfo: Align ci_info_init() assignment expressions Ahmed S. Darwish
2025-03-04 8:51 ` [PATCH v1 19/40] x86/cacheinfo: Standardize _cpuid4_info_regs instance naming Ahmed S. Darwish
2025-03-04 8:51 ` [PATCH v1 20/40] x86: treewide: Introduce x86_vendor_amd_or_hygon() Ahmed S. Darwish
2025-03-04 8:51 ` [PATCH v1 21/40] x86/cacheinfo: Consolidate AMD/Hygon leaf 0x8000001d calls Ahmed S. Darwish
2025-03-04 8:51 ` [PATCH v1 22/40] x86/cacheinfo: Separate amd_northbridge from _cpuid4_info_regs Ahmed S. Darwish
2025-03-04 8:51 ` [PATCH v1 23/40] x86/cacheinfo: Move AMD cache_disable_0/1 handling to separate file Ahmed S. Darwish
2025-03-04 8:51 ` [PATCH v1 24/40] x86/cacheinfo: Use sysfs_emit() for sysfs attributes show() Ahmed S. Darwish
2025-03-04 8:51 ` [PATCH v1 25/40] x86/cacheinfo: Separate Intel and AMD leaf 0x4 code paths Ahmed S. Darwish
2025-03-04 8:51 ` [PATCH v1 26/40] x86/cacheinfo: Rename _cpuid4_info_regs to _cpuid4_info Ahmed S. Darwish
2025-03-04 8:51 ` [PATCH v1 27/40] x86/cacheinfo: Clarify type markers for leaf 0x2 cache descriptors Ahmed S. Darwish
2025-03-04 8:51 ` [PATCH v1 28/40] x86/cacheinfo: Use enums for cache descriptor types Ahmed S. Darwish
2025-03-04 8:51 ` [PATCH v1 29/40] x86/cpu: Use enums for TLB " Ahmed S. Darwish
2025-03-04 8:51 ` [PATCH v1 30/40] sizes.h: Cover all possible x86 cpu cache sizes Ahmed S. Darwish
2025-03-04 9:35 ` Ingo Molnar
2025-03-05 16:18 ` Ahmed S. Darwish
2025-03-04 9:47 ` [tip: x86/cpu] <linux/sizes.h>: Cover all possible x86 CPU " tip-bot2 for Ahmed S. Darwish
2025-03-04 10:26 ` tip-bot2 for Ahmed S. Darwish
2025-03-04 8:51 ` [PATCH v1 31/40] x86/cpu: Consolidate CPUID leaf 0x2 tables Ahmed S. Darwish
2025-03-04 8:51 ` [PATCH v1 32/40] x86/cacheinfo: Use consolidated leaf 0x2 descriptor table Ahmed S. Darwish
2025-03-04 8:51 ` [PATCH v1 33/40] x86/cpu: " Ahmed S. Darwish
2025-03-04 8:51 ` [PATCH v1 34/40] x86/cacheinfo: Separate leaf 0x2 handling and post-processing logic Ahmed S. Darwish
2025-03-04 8:51 ` [PATCH v1 35/40] x86/cacheinfo: Separate intel leaf 0x4 handling Ahmed S. Darwish
2025-03-04 8:51 ` [PATCH v1 36/40] x86/cacheinfo: Extract out cache level topology ID calculation Ahmed S. Darwish
2025-03-04 8:51 ` [PATCH v1 37/40] x86/cacheinfo: Extract out cache self-snoop checks Ahmed S. Darwish
2025-03-04 10:38 ` Andrew Cooper [this message]
2025-03-05 18:40 ` Ahmed S. Darwish
2025-03-05 18:42 ` Andrew Cooper
2025-03-05 18:58 ` Ahmed S. Darwish
2025-03-05 19:01 ` Andrew Cooper
2025-03-04 8:51 ` [PATCH v1 38/40] x86/cacheinfo: Relocate leaf 0x4 cache_type mapping Ahmed S. Darwish
2025-03-04 8:51 ` [PATCH v1 39/40] x86/cacheinfo: Introduce amd_hygon_cpu_has_l3_cache() Ahmed S. Darwish
2025-03-04 8:51 ` [PATCH v1 40/40] x86/cacheinfo: Apply maintainer-tip coding style fixes Ahmed S. Darwish
2025-03-04 9:19 ` [PATCH v1 00/40] x86: Leaf 0x2 and leaf 0x4 refactorings Ingo Molnar
2025-03-04 9:38 ` Ingo Molnar
2025-03-05 17:36 ` Ahmed S. Darwish
2025-03-04 9:33 ` Ingo Molnar
2025-03-05 16:38 ` Ahmed S. Darwish
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