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From: Zide Chen <zide.chen@intel.com>
To: qemu-devel@nongnu.org, kvm@vger.kernel.org,
	Paolo Bonzini <pbonzini@redhat.com>,
	Zhao Liu <zhao1.liu@intel.com>, Peter Xu <peterx@redhat.com>,
	Fabiano Rosas <farosas@suse.de>
Cc: Xiaoyao Li <xiaoyao.li@intel.com>,
	Dongli Zhang <dongli.zhang@oracle.com>,
	Dapeng Mi <dapeng1.mi@linux.intel.com>,
	Zide Chen <zide.chen@intel.com>
Subject: [PATCH V2 07/11] target/i386: Make some PEBS features user-visible
Date: Wed, 28 Jan 2026 15:09:44 -0800	[thread overview]
Message-ID: <20260128231003.268981-8-zide.chen@intel.com> (raw)
In-Reply-To: <20260128231003.268981-1-zide.chen@intel.com>

Populate selected PEBS feature names in FEAT_PERF_CAPABILITIES to make
the corresponding bits user-visible CPU feature knobs, allowing them to
be explicitly enabled or disabled via -cpu +/-<feature>.

Once named, these bits become part of the guest CPU configuration
contract.  If a VM is configured with such a feature enabled, migration
to a destination that does not support the feature may fail, as the
destination cannot honor the guest-visible CPU model.

The PEBS_FMT bits are not exposed, as target/i386 currently does not
support multi-bit CPU properties.

Co-developed-by: Dapeng Mi <dapeng1.mi@linux.intel.com>
Signed-off-by: Dapeng Mi <dapeng1.mi@linux.intel.com>
Signed-off-by: Zide Chen <zide.chen@intel.com>
---
V2:
- Add the missing comma after "pebs-arch-reg".
- Simplify the PEBS_FMT description in the commit message.

 target/i386/cpu.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/target/i386/cpu.c b/target/i386/cpu.c
index d3e9d3c40b0a..f2c83b4f259c 100644
--- a/target/i386/cpu.c
+++ b/target/i386/cpu.c
@@ -1618,10 +1618,10 @@ FeatureWordInfo feature_word_info[FEATURE_WORDS] = {
         .type = MSR_FEATURE_WORD,
         .feat_names = {
             NULL, NULL, NULL, NULL,
+            NULL, NULL, "pebs-trap", "pebs-arch-reg",
             NULL, NULL, NULL, NULL,
-            NULL, NULL, NULL, NULL,
-            NULL, "full-width-write", NULL, NULL,
-            NULL, NULL, NULL, NULL,
+            NULL, "full-width-write", "pebs-baseline", NULL,
+            NULL, "pebs-timing-info", NULL, NULL,
             NULL, NULL, NULL, NULL,
             NULL, NULL, NULL, NULL,
             NULL, NULL, NULL, NULL,
-- 
2.52.0


  parent reply	other threads:[~2026-01-28 23:17 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-01-28 23:09 [PATCH V2 00/11] target/i386: Misc PMU, PEBS, and MSR fixes and improvements Zide Chen
2026-01-28 23:09 ` [PATCH V2 01/11] target/i386: Disable unsupported BTS for guest Zide Chen
2026-02-10  6:31   ` Mi, Dapeng
2026-02-11  6:14   ` Xiaoyao Li
2026-03-04 18:22     ` Chen, Zide
2026-01-28 23:09 ` [PATCH V2 02/11] target/i386: Don't save/restore PERF_GLOBAL_OVF_CTRL MSR Zide Chen
2026-01-28 23:09 ` [PATCH V2 03/11] target/i386: Gate enable_pmu on kvm_enabled() Zide Chen
2026-01-28 23:09 ` [PATCH V2 04/11] target/i386: Support full-width writes for perf counters Zide Chen
2026-01-28 23:09 ` [PATCH V2 05/11] target/i386: Increase MSR_BUF_SIZE and split KVM_[GET/SET]_MSRS calls Zide Chen
2026-02-10  6:57   ` Mi, Dapeng
2026-02-10 17:23     ` Chen, Zide
2026-01-28 23:09 ` [PATCH V2 06/11] target/i386: Save/Restore DS based PEBS specfic MSRs Zide Chen
2026-01-28 23:09 ` Zide Chen [this message]
2026-02-10  7:02   ` [PATCH V2 07/11] target/i386: Make some PEBS features user-visible Mi, Dapeng
2026-01-28 23:09 ` [PATCH V2 08/11] target/i386: Clean up LBR format handling Zide Chen
2026-02-10  7:07   ` Mi, Dapeng
2026-01-28 23:09 ` [PATCH V2 09/11] target/i386: Refactor " Zide Chen
2026-02-10  7:14   ` Mi, Dapeng
2026-01-28 23:09 ` [PATCH V2 10/11] target/i386: Add pebs-fmt CPU option Zide Chen
2026-01-28 23:09 ` [PATCH V2 11/11] target/i386: Disable guest PEBS capability when not enabled Zide Chen
2026-02-10  7:30   ` Mi, Dapeng
2026-02-10 19:05     ` Chen, Zide
2026-02-11  1:20       ` Mi, Dapeng

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