Re: [PATCH v2] perf/x86/amd: Don't touch the AMD64_EVENTSEL_HOSTONLY bit inside the guest

On Wed, Aug 04, 2021 at 12:28:54PM +0100, Liam Merwick wrote:

On (08/02/21 15:08), Like Xu wrote:

quoted

From: Like Xu <redacted>

If we use "perf record" in an AMD Milan guest, dmesg reports a #GP
warning from an unchecked MSR access error on MSR_F15H_PERF_CTLx:

[] unchecked MSR access error: WRMSR to 0xc0010200 (tried to write
0x0000020000110076) at rIP: 0xffffffff8106ddb4 (native_write_msr+0x4/0x20)
[] Call Trace:
[]  amd_pmu_disable_event+0x22/0x90
[]  x86_pmu_stop+0x4c/0xa0
[]  x86_pmu_del+0x3a/0x140

The AMD64_EVENTSEL_HOSTONLY bit is defined and used on the host,
while the guest perf driver should avoid such use.

Fixes: 1018faa6cf23 ("perf/x86/kvm: Fix Host-Only/Guest-Only counting with SVM disabled")
Signed-off-by: Like Xu <redacted>
Tested-by: Kim Phillips <redacted>

Reviewed-by: Liam Merwick <redacted>
Tested-by: Liam Merwick <redacted>
[ Patch applied to a 5.4 branch ]

Should it also include

Cc: stable@vger.kernel.org

An accurate Fixes tag is usually sufficient to trigger the stable
robots. Anyway, thanks!