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* [PATCH v2] perf/x86/amd: Don't touch the AMD64_EVENTSEL_HOSTONLY bit inside the guest
@ 2021-08-02  7:08 Like Xu
  2021-08-04 11:28 ` Liam Merwick
  2021-08-05  9:34 ` [tip: perf/urgent] " tip-bot2 for Like Xu
  0 siblings, 2 replies; 4+ messages in thread
From: Like Xu @ 2021-08-02  7:08 UTC (permalink / raw)
  To: Peter Zijlstra, Joerg Roedel
  Cc: Ingo Molnar, Arnaldo Carvalho de Melo, Mark Rutland,
	Alexander Shishkin, Jiri Olsa, Namhyung Kim, Thomas Gleixner,
	Borislav Petkov, x86, H . Peter Anvin, linux-perf-users,
	linux-kernel

From: Like Xu <likexu@tencent.com>

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 <likexu@tencent.com>
Tested-by: Kim Phillips <kim.phillips@amd.com>
---
v2: Add Fixes tag and Tested-by from Kim.
v1: https://lore.kernel.org/lkml/20210720112605.63286-1-likexu@tencent.com/

 arch/x86/events/perf_event.h | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/x86/events/perf_event.h b/arch/x86/events/perf_event.h
index d6003e08b055..1c3ae954a230 100644
--- a/arch/x86/events/perf_event.h
+++ b/arch/x86/events/perf_event.h
@@ -1116,8 +1116,9 @@ void x86_pmu_stop(struct perf_event *event, int flags);
 static inline void x86_pmu_disable_event(struct perf_event *event)
 {
 	struct hw_perf_event *hwc = &event->hw;
+	u64 disable_mask = __this_cpu_read(cpu_hw_events.perf_ctr_virt_mask);
 
-	wrmsrl(hwc->config_base, hwc->config);
+	wrmsrl(hwc->config_base, hwc->config & ~disable_mask);
 
 	if (is_counter_pair(hwc))
 		wrmsrl(x86_pmu_config_addr(hwc->idx + 1), 0);
-- 
2.32.0


^ permalink raw reply related	[flat|nested] 4+ messages in thread

* Re: [PATCH v2] perf/x86/amd: Don't touch the AMD64_EVENTSEL_HOSTONLY bit inside the guest
  2021-08-02  7:08 [PATCH v2] perf/x86/amd: Don't touch the AMD64_EVENTSEL_HOSTONLY bit inside the guest Like Xu
@ 2021-08-04 11:28 ` Liam Merwick
  2021-08-04 13:02   ` Peter Zijlstra
  2021-08-05  9:34 ` [tip: perf/urgent] " tip-bot2 for Like Xu
  1 sibling, 1 reply; 4+ messages in thread
From: Liam Merwick @ 2021-08-04 11:28 UTC (permalink / raw)
  To: Like Xu
  Cc: Peter Zijlstra, Joerg Roedel, Ingo Molnar,
	Arnaldo Carvalho de Melo, Mark Rutland, Alexander Shishkin,
	Jiri Olsa, Namhyung Kim, Thomas Gleixner, liam.merwick,
	Borislav Petkov, x86, H . Peter Anvin, linux-perf-users,
	linux-kernel

On (08/02/21 15:08), Like Xu wrote:
> Date:   Mon,  2 Aug 2021 15:08:50 +0800
> From: Like Xu <like.xu.linux@gmail.com>
> To: Peter Zijlstra <peterz@infradead.org>, Joerg Roedel
>  <joerg.roedel@amd.com>
> Cc: Ingo Molnar <mingo@redhat.com>, Arnaldo Carvalho de Melo
>  <acme@kernel.org>, Mark Rutland <mark.rutland@arm.com>, Alexander Shishkin
>  <alexander.shishkin@linux.intel.com>, Jiri Olsa <jolsa@redhat.com>,
>  Namhyung Kim <namhyung@kernel.org>, Thomas Gleixner <tglx@linutronix.de>,
>  Borislav Petkov <bp@alien8.de>, x86@kernel.org, "H . Peter Anvin"
>  <hpa@zytor.com>, linux-perf-users@vger.kernel.org,
>  linux-kernel@vger.kernel.org
> Subject: [PATCH v2] perf/x86/amd: Don't touch the AMD64_EVENTSEL_HOSTONLY
>  bit inside the guest
> X-Mailer: git-send-email 2.32.0
> 
> From: Like Xu <likexu@tencent.com>
> 
> 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 <likexu@tencent.com>
> Tested-by: Kim Phillips <kim.phillips@amd.com>

Reviewed-by: Liam Merwick <liam.merwick@oracle.com>
Tested-by: Liam Merwick <liam.merwick@oracle.com>
[ Patch applied to a 5.4 branch ]

Should it also include

Cc: stable@vger.kernel.org

Regards,
Liam

> ---
> v2: Add Fixes tag and Tested-by from Kim.
> v1: https://lore.kernel.org/lkml/20210720112605.63286-1-likexu@tencent.com/
> 
>  arch/x86/events/perf_event.h | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/x86/events/perf_event.h b/arch/x86/events/perf_event.h
> index d6003e08b055..1c3ae954a230 100644
> --- a/arch/x86/events/perf_event.h
> +++ b/arch/x86/events/perf_event.h
> @@ -1116,8 +1116,9 @@ void x86_pmu_stop(struct perf_event *event, int flags);
>  static inline void x86_pmu_disable_event(struct perf_event *event)
>  {
>  	struct hw_perf_event *hwc = &event->hw;
> +	u64 disable_mask = __this_cpu_read(cpu_hw_events.perf_ctr_virt_mask);
>  
> -	wrmsrl(hwc->config_base, hwc->config);
> +	wrmsrl(hwc->config_base, hwc->config & ~disable_mask);
>  
>  	if (is_counter_pair(hwc))
>  		wrmsrl(x86_pmu_config_addr(hwc->idx + 1), 0);
> -- 
> 2.32.0
> 

^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: [PATCH v2] perf/x86/amd: Don't touch the AMD64_EVENTSEL_HOSTONLY bit inside the guest
  2021-08-04 11:28 ` Liam Merwick
@ 2021-08-04 13:02   ` Peter Zijlstra
  0 siblings, 0 replies; 4+ messages in thread
From: Peter Zijlstra @ 2021-08-04 13:02 UTC (permalink / raw)
  To: Liam Merwick
  Cc: Like Xu, Joerg Roedel, Ingo Molnar, Arnaldo Carvalho de Melo,
	Mark Rutland, Alexander Shishkin, Jiri Olsa, Namhyung Kim,
	Thomas Gleixner, Borislav Petkov, x86, H . Peter Anvin,
	linux-perf-users, linux-kernel

On Wed, Aug 04, 2021 at 12:28:54PM +0100, Liam Merwick wrote:
> On (08/02/21 15:08), Like Xu wrote:

> > From: Like Xu <likexu@tencent.com>
> > 
> > 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 <likexu@tencent.com>
> > Tested-by: Kim Phillips <kim.phillips@amd.com>
> 
> Reviewed-by: Liam Merwick <liam.merwick@oracle.com>
> Tested-by: Liam Merwick <liam.merwick@oracle.com>
> [ 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!

^ permalink raw reply	[flat|nested] 4+ messages in thread

* [tip: perf/urgent] perf/x86/amd: Don't touch the AMD64_EVENTSEL_HOSTONLY bit inside the guest
  2021-08-02  7:08 [PATCH v2] perf/x86/amd: Don't touch the AMD64_EVENTSEL_HOSTONLY bit inside the guest Like Xu
  2021-08-04 11:28 ` Liam Merwick
@ 2021-08-05  9:34 ` tip-bot2 for Like Xu
  1 sibling, 0 replies; 4+ messages in thread
From: tip-bot2 for Like Xu @ 2021-08-05  9:34 UTC (permalink / raw)
  To: linux-tip-commits
  Cc: Like Xu, Peter Zijlstra (Intel),
	Liam Merwick, Kim Phillips, x86, linux-kernel

The following commit has been merged into the perf/urgent branch of tip:

Commit-ID:     df51fe7ea1c1c2c3bfdb81279712fdd2e4ea6c27
Gitweb:        https://git.kernel.org/tip/df51fe7ea1c1c2c3bfdb81279712fdd2e4ea6c27
Author:        Like Xu <likexu@tencent.com>
AuthorDate:    Mon, 02 Aug 2021 15:08:50 +08:00
Committer:     Peter Zijlstra <peterz@infradead.org>
CommitterDate: Wed, 04 Aug 2021 15:16:34 +02:00

perf/x86/amd: Don't touch the AMD64_EVENTSEL_HOSTONLY bit inside the guest

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 <likexu@tencent.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Liam Merwick <liam.merwick@oracle.com>
Tested-by: Kim Phillips <kim.phillips@amd.com>
Tested-by: Liam Merwick <liam.merwick@oracle.com>
Link: https://lkml.kernel.org/r/20210802070850.35295-1-likexu@tencent.com
---
 arch/x86/events/perf_event.h | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/x86/events/perf_event.h b/arch/x86/events/perf_event.h
index 2bf1c7e..2938c90 100644
--- a/arch/x86/events/perf_event.h
+++ b/arch/x86/events/perf_event.h
@@ -1115,9 +1115,10 @@ void x86_pmu_stop(struct perf_event *event, int flags);
 
 static inline void x86_pmu_disable_event(struct perf_event *event)
 {
+	u64 disable_mask = __this_cpu_read(cpu_hw_events.perf_ctr_virt_mask);
 	struct hw_perf_event *hwc = &event->hw;
 
-	wrmsrl(hwc->config_base, hwc->config);
+	wrmsrl(hwc->config_base, hwc->config & ~disable_mask);
 
 	if (is_counter_pair(hwc))
 		wrmsrl(x86_pmu_config_addr(hwc->idx + 1), 0);

^ permalink raw reply related	[flat|nested] 4+ messages in thread

end of thread, other threads:[~2021-08-05  9:34 UTC | newest]

Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
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2021-08-02  7:08 [PATCH v2] perf/x86/amd: Don't touch the AMD64_EVENTSEL_HOSTONLY bit inside the guest Like Xu
2021-08-04 11:28 ` Liam Merwick
2021-08-04 13:02   ` Peter Zijlstra
2021-08-05  9:34 ` [tip: perf/urgent] " tip-bot2 for Like Xu

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