* [PATCH] x86/hyperv/vtl: Stop kernel from probing VTL0 low memory
@ 2025-01-16 6:12 Naman Jain
2025-01-17 17:01 ` Roman Kisel
0 siblings, 1 reply; 3+ messages in thread
From: Naman Jain @ 2025-01-16 6:12 UTC (permalink / raw)
To: K . Y . Srinivasan, Haiyang Zhang, Wei Liu, Dexuan Cui,
Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen, x86
Cc: linux-hyperv, linux-kernel, Saurabh Sengar
For Linux, running in Hyper-V VTL (Virtual Trust Level), kernel in VTL2
tries to access VTL0 low memory in probe_roms. This memory is not
described in the e820 map. Initialize probe_roms call to no-ops
during boot for VTL2 kernel to avoid this. The issue got identified
in OpenVMM which detects invalid accesses initiated from kernel running
in VTL2.
Co-developed-by: Saurabh Sengar <ssengar@linux.microsoft.com>
Signed-off-by: Saurabh Sengar <ssengar@linux.microsoft.com>
Signed-off-by: Naman Jain <namjain@linux.microsoft.com>
---
arch/x86/hyperv/hv_vtl.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/arch/x86/hyperv/hv_vtl.c b/arch/x86/hyperv/hv_vtl.c
index 4e1b1e3b5658..3f4e20d7b724 100644
--- a/arch/x86/hyperv/hv_vtl.c
+++ b/arch/x86/hyperv/hv_vtl.c
@@ -30,6 +30,7 @@ void __init hv_vtl_init_platform(void)
x86_platform.realmode_init = x86_init_noop;
x86_init.irqs.pre_vector_init = x86_init_noop;
x86_init.timers.timer_init = x86_init_noop;
+ x86_init.resources.probe_roms = x86_init_noop;
/* Avoid searching for BIOS MP tables */
x86_init.mpparse.find_mptable = x86_init_noop;
base-commit: 37136bf5c3a6f6b686d74f41837a6406bec6b7bc
--
2.43.0
^ permalink raw reply related [flat|nested] 3+ messages in thread
* [PATCH] x86/hyperv/vtl: Stop kernel from probing VTL0 low memory
2025-01-16 6:12 [PATCH] x86/hyperv/vtl: Stop kernel from probing VTL0 low memory Naman Jain
@ 2025-01-17 17:01 ` Roman Kisel
2025-02-12 2:17 ` Wei Liu
0 siblings, 1 reply; 3+ messages in thread
From: Roman Kisel @ 2025-01-17 17:01 UTC (permalink / raw)
To: namjain
Cc: bp, dave.hansen, decui, haiyangz, kys, linux-hyperv, linux-kernel,
mingo, ssengar, tglx, wei.liu, x86
> For Linux, running in Hyper-V VTL (Virtual Trust Level), kernel in VTL2
> tries to access VTL0 low memory in probe_roms. This memory is not
> described in the e820 map. Initialize probe_roms call to no-ops
> during boot for VTL2 kernel to avoid this. The issue got identified
> in OpenVMM which detects invalid accesses initiated from kernel running
> in VTL2.
>
> Co-developed-by: Saurabh Sengar <ssengar@linux.microsoft.com>
> Signed-off-by: Saurabh Sengar <ssengar@linux.microsoft.com>
> Signed-off-by: Naman Jain <namjain@linux.microsoft.com>
> ---
> arch/x86/hyperv/hv_vtl.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/arch/x86/hyperv/hv_vtl.c b/arch/x86/hyperv/hv_vtl.c
> index 4e1b1e3b5658..3f4e20d7b724 100644
> --- a/arch/x86/hyperv/hv_vtl.c
> +++ b/arch/x86/hyperv/hv_vtl.c
> @@ -30,6 +30,7 @@ void __init hv_vtl_init_platform(void)
> x86_platform.realmode_init = x86_init_noop;
> x86_init.irqs.pre_vector_init = x86_init_noop;
> x86_init.timers.timer_init = x86_init_noop;
> + x86_init.resources.probe_roms = x86_init_noop;
>
> /* Avoid searching for BIOS MP tables */
> x86_init.mpparse.find_mptable = x86_init_noop;
>
> base-commit: 37136bf5c3a6f6b686d74f41837a6406bec6b7bc
> --
> 2.43.0
Thanks, Naman!
Tested-by: Roman Kisel <romank@linux.microsoft.com>
Reviewed-by: Roman Kisel <romank@linux.microsoft.com>
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] x86/hyperv/vtl: Stop kernel from probing VTL0 low memory
2025-01-17 17:01 ` Roman Kisel
@ 2025-02-12 2:17 ` Wei Liu
0 siblings, 0 replies; 3+ messages in thread
From: Wei Liu @ 2025-02-12 2:17 UTC (permalink / raw)
To: Roman Kisel
Cc: namjain, bp, dave.hansen, decui, haiyangz, kys, linux-hyperv,
linux-kernel, mingo, ssengar, tglx, wei.liu, x86
On Fri, Jan 17, 2025 at 09:01:41AM -0800, Roman Kisel wrote:
> > For Linux, running in Hyper-V VTL (Virtual Trust Level), kernel in VTL2
> > tries to access VTL0 low memory in probe_roms. This memory is not
> > described in the e820 map. Initialize probe_roms call to no-ops
> > during boot for VTL2 kernel to avoid this. The issue got identified
> > in OpenVMM which detects invalid accesses initiated from kernel running
> > in VTL2.
> >
> > Co-developed-by: Saurabh Sengar <ssengar@linux.microsoft.com>
> > Signed-off-by: Saurabh Sengar <ssengar@linux.microsoft.com>
> > Signed-off-by: Naman Jain <namjain@linux.microsoft.com>
> > ---
> > arch/x86/hyperv/hv_vtl.c | 1 +
> > 1 file changed, 1 insertion(+)
> >
> > diff --git a/arch/x86/hyperv/hv_vtl.c b/arch/x86/hyperv/hv_vtl.c
> > index 4e1b1e3b5658..3f4e20d7b724 100644
> > --- a/arch/x86/hyperv/hv_vtl.c
> > +++ b/arch/x86/hyperv/hv_vtl.c
> > @@ -30,6 +30,7 @@ void __init hv_vtl_init_platform(void)
> > x86_platform.realmode_init = x86_init_noop;
> > x86_init.irqs.pre_vector_init = x86_init_noop;
> > x86_init.timers.timer_init = x86_init_noop;
> > + x86_init.resources.probe_roms = x86_init_noop;
> >
> > /* Avoid searching for BIOS MP tables */
> > x86_init.mpparse.find_mptable = x86_init_noop;
> >
> > base-commit: 37136bf5c3a6f6b686d74f41837a6406bec6b7bc
> > --
> > 2.43.0
>
> Thanks, Naman!
>
> Tested-by: Roman Kisel <romank@linux.microsoft.com>
> Reviewed-by: Roman Kisel <romank@linux.microsoft.com>
Applied to hyperv-fixes. Thanks.
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2025-02-12 2:17 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2025-01-16 6:12 [PATCH] x86/hyperv/vtl: Stop kernel from probing VTL0 low memory Naman Jain
2025-01-17 17:01 ` Roman Kisel
2025-02-12 2:17 ` Wei Liu
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).