* [PATCH v3] perf/x86/amd: Don't touch the Host-only bit inside the guest hypervisor
@ 2022-03-14 4:22 Dongli Si
2022-03-16 18:29 ` Borislav Petkov
0 siblings, 1 reply; 4+ messages in thread
From: Dongli Si @ 2022-03-14 4:22 UTC (permalink / raw)
To: peterz, joerg.roedel
Cc: liam.merwick, kim.phillips, mingo, acme, mark.rutland,
alexander.shishkin, jolsa, namhyung, tglx, bp, dave.hansen, x86,
hpa, linux-perf-users, linux-kernel
From: Dongli Si <sidongli1997@gmail.com>
With nested virtualization on AMD Milan, if "perf record" is run in an
L1 hypervisor with an L2 guest, the following warning is emitted in
the L1 guest.
[] unchecked MSR access error: WRMSR to 0xc0010200 (tried to write 0x0000020000510076)
at rIP: 0xffffffff81003a50 (x86_pmu_enable_all+0x60/0x100)
[] Call Trace:
[] <IRQ>
[] ? x86_pmu_enable+0x146/0x300
[] __perf_install_in_context+0x150/0x170
The AMD64_EVENTSEL_HOSTONLY bit is defined and used on the host (L0),
while the L1 hypervisor Performance Monitor Unit should avoid such use.
Fixes: 1018faa6cf23 ("perf/x86/kvm: Fix Host-Only/Guest-Only counting with SVM disabled")
Signed-off-by: Dongli Si <sidongli1997@gmail.com>
Tested-by: Liam Merwick <liam.merwick@oracle.com>
Reviewed-by: Liam Merwick <liam.merwick@oracle.com>
---
v3: Add Tested-by, Reviewed-by from Liam and improve description.
v2: https://lore.kernel.org/all/20220310183404.1291725-1-sidongli1997@gmail.com/
v1: https://lore.kernel.org/all/20220227132640.3-1-sidongli1997@gmail.com/
arch/x86/events/amd/core.c | 4 +++-
arch/x86/include/asm/hypervisor.h | 10 ++++++++++
2 files changed, 13 insertions(+), 1 deletion(-)
diff --git a/arch/x86/events/amd/core.c b/arch/x86/events/amd/core.c
index 9687a8aef01c..14cd079243a4 100644
--- a/arch/x86/events/amd/core.c
+++ b/arch/x86/events/amd/core.c
@@ -8,6 +8,7 @@
#include <linux/jiffies.h>
#include <asm/apicdef.h>
#include <asm/nmi.h>
+#include <asm/hypervisor.h>
#include "../perf_event.h"
@@ -1027,7 +1028,8 @@ void amd_pmu_enable_virt(void)
{
struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
- cpuc->perf_ctr_virt_mask = 0;
+ if (run_as_host())
+ cpuc->perf_ctr_virt_mask = 0;
/* Reload all events */
amd_pmu_disable_all();
diff --git a/arch/x86/include/asm/hypervisor.h b/arch/x86/include/asm/hypervisor.h
index e41cbf2ec41d..fcc66c23cc72 100644
--- a/arch/x86/include/asm/hypervisor.h
+++ b/arch/x86/include/asm/hypervisor.h
@@ -73,11 +73,21 @@ static inline bool hypervisor_is_type(enum x86_hypervisor_type type)
{
return x86_hyper_type == type;
}
+
+static inline bool run_as_host(void)
+{
+ return hypervisor_is_type(X86_HYPER_NATIVE);
+}
#else
static inline void init_hypervisor_platform(void) { }
static inline bool hypervisor_is_type(enum x86_hypervisor_type type)
{
return type == X86_HYPER_NATIVE;
}
+
+static inline bool run_as_host(void)
+{
+ return true;
+}
#endif /* CONFIG_HYPERVISOR_GUEST */
#endif /* _ASM_X86_HYPERVISOR_H */
--
2.32.0
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH v3] perf/x86/amd: Don't touch the Host-only bit inside the guest hypervisor
2022-03-14 4:22 [PATCH v3] perf/x86/amd: Don't touch the Host-only bit inside the guest hypervisor Dongli Si
@ 2022-03-16 18:29 ` Borislav Petkov
2022-03-18 3:07 ` Dongli Si
0 siblings, 1 reply; 4+ messages in thread
From: Borislav Petkov @ 2022-03-16 18:29 UTC (permalink / raw)
To: Dongli Si
Cc: peterz, joerg.roedel, liam.merwick, kim.phillips, mingo, acme,
mark.rutland, alexander.shishkin, jolsa, namhyung, tglx,
dave.hansen, x86, hpa, linux-perf-users, linux-kernel
On Mon, Mar 14, 2022 at 12:22:54PM +0800, Dongli Si wrote:
> diff --git a/arch/x86/include/asm/hypervisor.h b/arch/x86/include/asm/hypervisor.h
> index e41cbf2ec41d..fcc66c23cc72 100644
> --- a/arch/x86/include/asm/hypervisor.h
> +++ b/arch/x86/include/asm/hypervisor.h
> @@ -73,11 +73,21 @@ static inline bool hypervisor_is_type(enum x86_hypervisor_type type)
> {
> return x86_hyper_type == type;
> }
> +
> +static inline bool run_as_host(void)
> +{
> + return hypervisor_is_type(X86_HYPER_NATIVE);
> +}
What's the point of this "wrapper"?
--
Regards/Gruss,
Boris.
https://people.kernel.org/tglx/notes-about-netiquette
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH v3] perf/x86/amd: Don't touch the Host-only bit inside the guest hypervisor
2022-03-16 18:29 ` Borislav Petkov
@ 2022-03-18 3:07 ` Dongli Si
2022-03-18 18:50 ` Borislav Petkov
0 siblings, 1 reply; 4+ messages in thread
From: Dongli Si @ 2022-03-18 3:07 UTC (permalink / raw)
To: bp
Cc: acme, alexander.shishkin, dave.hansen, hpa, joerg.roedel, jolsa,
kim.phillips, kvmx86, liam.merwick, linux-kernel,
linux-perf-users, mark.rutland, mingo, namhyung, peterz, tglx,
x86
On 16/03/2022 18:29, Borislav Petkov wrote:
> What's the point of this "wrapper"?
Hi Borislav, this is just to more clearly test if the current kernel is
running directly on the host.
If this is redundant, I can remove this "wrapper" and resend the patch,
the v4 patch code will be the same as the v1 patch.
Thanks,
Dongli
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH v3] perf/x86/amd: Don't touch the Host-only bit inside the guest hypervisor
2022-03-18 3:07 ` Dongli Si
@ 2022-03-18 18:50 ` Borislav Petkov
0 siblings, 0 replies; 4+ messages in thread
From: Borislav Petkov @ 2022-03-18 18:50 UTC (permalink / raw)
To: Dongli Si
Cc: acme, alexander.shishkin, dave.hansen, hpa, joerg.roedel, jolsa,
kim.phillips, liam.merwick, linux-kernel, linux-perf-users,
mark.rutland, mingo, namhyung, peterz, tglx, x86
On Fri, Mar 18, 2022 at 11:07:57AM +0800, Dongli Si wrote:
> Hi Borislav, this is just to more clearly test if the current kernel is
> running directly on the host.
>
> If this is redundant, I can remove this "wrapper" and resend the patch,
> the v4 patch code will be the same as the v1 patch.
Yes please. Using
hypervisor_is_type(X86_HYPER_NATIVE)
directly is a lot more descriptive than "run_as_host".
Thx.
--
Regards/Gruss,
Boris.
https://people.kernel.org/tglx/notes-about-netiquette
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2022-03-18 18:51 UTC | newest]
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2022-03-14 4:22 [PATCH v3] perf/x86/amd: Don't touch the Host-only bit inside the guest hypervisor Dongli Si
2022-03-16 18:29 ` Borislav Petkov
2022-03-18 3:07 ` Dongli Si
2022-03-18 18:50 ` Borislav Petkov
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