[PATCH v1] target/i386: set the CPUID level to 0x14 on old machine-type

[PATCH v1] target/i386: set the CPUID level to 0x14 on old machine-type

[Luwei Kang]

The CPUID level need to be set to 0x14 manually on old
machine-type if Intel PT is enabled in guest. e.g. in Qemu 3.1
-machine pc-i440fx-3.1 -cpu qemu64,+intel-pt
will be CPUID[0].EAX(level)=7 and CPUID[7].EBX[25](intel-pt)=1.

Some Intel PT capabilities are exposed by leaf 0x14 and the
missing capabilities will cause some MSRs access failed.
This patch add a warning message to inform the user to extend
the CPUID level.

Suggested-by: Eduardo Habkost <ehabkost@redhat.com>
Signed-off-by: Luwei Kang <luwei.kang@intel.com>
---
 target/i386/cpu.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/target/i386/cpu.c b/target/i386/cpu.c
index 47200b4..9abbd30 100644
--- a/target/i386/cpu.c
+++ b/target/i386/cpu.c
@@ -5393,8 +5393,12 @@ static void x86_cpu_expand_features(X86CPU *cpu, Error **errp)
 
         /* Intel Processor Trace requires CPUID[0x14] */
         if ((env->features[FEAT_7_0_EBX] & CPUID_7_0_EBX_INTEL_PT) &&
-             kvm_enabled() && cpu->intel_pt_auto_level) {
-            x86_cpu_adjust_level(cpu, &cpu->env.cpuid_min_level, 0x14);
+             kvm_enabled()) {
+            if (cpu->intel_pt_auto_level)
+                x86_cpu_adjust_level(cpu, &cpu->env.cpuid_min_level, 0x14);
+            else
+                warn_report("Intel PT need CPUID leaf 0x14, please set "
+                            "by \"-cpu ...,+intel-pt,level=0x14\"\n");
         }
 
         /* CPU topology with multi-dies support requires CPUID[0x1F] */
-- 
1.8.3.1

Re: [PATCH v1] target/i386: set the CPUID level to 0x14 on old machine-type

[no-reply]

Patchew URL: https://patchew.org/QEMU/1572413233-27015-1-git-send-email-luwei.kang@intel.com/



Hi,

This series seems to have some coding style problems. See output below for
more information:

Subject: [PATCH v1] target/i386: set the CPUID level to 0x14 on old machine-type
Type: series
Message-id: 1572413233-27015-1-git-send-email-luwei.kang@intel.com

=== TEST SCRIPT BEGIN ===
#!/bin/bash
git rev-parse base > /dev/null || exit 0
git config --local diff.renamelimit 0
git config --local diff.renames True
git config --local diff.algorithm histogram
./scripts/checkpatch.pl --mailback base..
=== TEST SCRIPT END ===

Switched to a new branch 'test'
c5736fe target/i386: set the CPUID level to 0x14 on old machine-type

=== OUTPUT BEGIN ===
ERROR: Error messages should not contain newlines
#36: FILE: target/i386/cpu.c:5448:
+                            "by \"-cpu ...,+intel-pt,level=0x14\"\n");

total: 1 errors, 0 warnings, 14 lines checked

Commit c5736fe95d3f (target/i386: set the CPUID level to 0x14 on old machine-type) has style problems, please review.  If any of these errors
are false positives report them to the maintainer, see
CHECKPATCH in MAINTAINERS.
=== OUTPUT END ===

Test command exited with code: 1


The full log is available at
http://patchew.org/logs/1572413233-27015-1-git-send-email-luwei.kang@intel.com/testing.checkpatch/?type=message.
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