From: Mukesh R <mrathor@linux.microsoft.com>
To: Borislav Petkov <bp@alien8.de>
Cc: linux-hyperv@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-arch@vger.kernel.org, kys@microsoft.com,
haiyangz@microsoft.com, wei.liu@kernel.org, decui@microsoft.com,
tglx@linutronix.de, mingo@redhat.com,
dave.hansen@linux.intel.com, x86@kernel.org, hpa@zytor.com,
arnd@arndb.de
Subject: Re: [PATCH v3 5/6] x86/hyperv: Implement hypervisor RAM collection into vmcore
Date: Tue, 13 Jan 2026 15:36:51 -0800 [thread overview]
Message-ID: <88b38aff-51b8-57d8-e548-00d42254a541@linux.microsoft.com> (raw)
In-Reply-To: <20260113111412.GAaWYpBFPPLRG-YxNt@fat_crate.local>
On 1/13/26 03:14, Borislav Petkov wrote:
> On Mon, Oct 06, 2025 at 03:42:07PM -0700, Mukesh Rathor wrote:
>> Introduce a new file to implement collection of hypervisor RAM into the
>> vmcore collected by linux. By default, the hypervisor RAM is locked, ie,
>> protected via hw page table. Hyper-V implements a disable hypercall which
>> essentially devirtualizes the system on the fly. This mechanism makes the
>> hypervisor RAM accessible to linux. Because the hypervisor RAM is already
>> mapped into linux address space (as reserved RAM), it is automatically
>> collected into the vmcore without extra work. More details of the
>> implementation are available in the file prologue.
>>
>> Signed-off-by: Mukesh Rathor <mrathor@linux.microsoft.com>
>> ---
>> arch/x86/hyperv/hv_crash.c | 642 +++++++++++++++++++++++++++++++++++++
>> 1 file changed, 642 insertions(+)
>> create mode 100644 arch/x86/hyperv/hv_crash.c
>
> This breaks randconfig builds here:
>
> arch/x86/hyperv/hv_crash.c:631:2: error: must use 'struct' tag to refer to type 'smp_ops'
> 631 | smp_ops.crash_stop_other_cpus = hv_crash_stop_other_cpus;
> | ^
> | struct
> arch/x86/hyperv/hv_crash.c:631:9: error: expected identifier or '('
> 631 | smp_ops.crash_stop_other_cpus = hv_crash_stop_other_cpus;
> | ^
> 2 errors generated.
> make[4]: *** [scripts/Makefile.build:287: arch/x86/hyperv/hv_crash.o] Error 1
> make[4]: *** Waiting for unfinished jobs....
> make[3]: *** [scripts/Makefile.build:544: arch/x86/hyperv] Error 2
> make[3]: *** Waiting for unfinished jobs....
> make[2]: *** [scripts/Makefile.build:544: arch/x86] Error 2
> make[2]: *** Waiting for unfinished jobs....
> make[1]: *** [/home/amd/kernel/linux/Makefile:2054: .] Error 2
> make: *** [Makefile:248: __sub-make] Error 2
>
> config 01-18-21-randconfig-x86_64-13708.cfg attached. Note that this is
> a clang build:
>
> Ubuntu clang version 18.1.3 (1ubuntu1)
>
> It fails with gcc too tho:
>
> arch/x86/hyperv/hv_crash.c: In function ?hv_root_crash_init?:
> arch/x86/hyperv/hv_crash.c:631:9: error: ?smp_ops? undeclared (first use in this function)
> 631 | smp_ops.crash_stop_other_cpus = hv_crash_stop_other_cpus;
> | ^~~~~~~
> arch/x86/hyperv/hv_crash.c:631:9: note: each undeclared identifier is reported only once for each function it appears in
> make[4]: *** [scripts/Makefile.build:287: arch/x86/hyperv/hv_crash.o] Error 1
> make[4]: *** Waiting for unfinished jobs....
> make[3]: *** [scripts/Makefile.build:544: arch/x86/hyperv] Error 2
> make[3]: *** Waiting for unfinished jobs....
> make[2]: *** [scripts/Makefile.build:544: arch/x86] Error 2
> make[2]: *** Waiting for unfinished jobs....
> make[1]: *** [/home/amd/kernel/linux/Makefile:2054: .] Error 2
> make: *** [Makefile:248: __sub-make] Error 2
>
Looks like needs some config option around it, probably SMP. Will take
a look in a day or two. Thanks for letting us know.
-Mukesh
next prev parent reply other threads:[~2026-01-13 23:36 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-10-06 22:42 [PATCH v3 0/6] Hyper-V: Implement hypervisor core collection Mukesh Rathor
2025-10-06 22:42 ` [PATCH v3 1/6] x86/hyperv: Rename guest crash shutdown function Mukesh Rathor
2025-10-06 22:42 ` [PATCH v3 2/6] hyperv: Add two new hypercall numbers to guest ABI public header Mukesh Rathor
2025-10-06 22:42 ` [PATCH v3 3/6] hyperv: Add definitions for hypervisor crash dump support Mukesh Rathor
2025-10-06 22:42 ` [PATCH v3 4/6] x86/hyperv: Add trampoline asm code to transition from hypervisor Mukesh Rathor
2025-10-06 22:42 ` [PATCH v3 5/6] x86/hyperv: Implement hypervisor RAM collection into vmcore Mukesh Rathor
2026-01-13 11:14 ` Borislav Petkov
2026-01-13 23:36 ` Mukesh R [this message]
2025-10-06 22:42 ` [PATCH v3 6/6] x86/hyperv: Enable build of hypervisor crashdump collection files Mukesh Rathor
2025-10-17 22:33 ` [PATCH v3 0/6] Hyper-V: Implement hypervisor core collection Wei Liu
2025-10-17 22:57 ` Wei Liu
2025-10-17 23:58 ` Mukesh R
2025-10-18 2:54 ` Michael Kelley
2025-10-20 19:05 ` Mukesh R
2025-10-20 20:48 ` Wei Liu
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