From: Dave Hansen <dave.hansen@intel.com>
To: Vishal Annapurve <vannapurve@google.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>,
linux-kernel@vger.kernel.org, kvm@vger.kernel.org, bp@alien8.de,
tglx@linutronix.de, peterz@infradead.org, mingo@redhat.com,
hpa@zytor.com, thomas.lendacky@amd.com, x86@kernel.org,
kas@kernel.org, rick.p.edgecombe@intel.com, dwmw@amazon.co.uk,
kai.huang@intel.com, seanjc@google.com,
reinette.chatre@intel.com, isaku.yamahata@intel.com,
dan.j.williams@intel.com, ashish.kalra@amd.com,
nik.borisov@suse.com, chao.gao@intel.com, sagis@google.com,
farrah.chen@intel.com, Binbin Wu <binbin.wu@linux.intel.com>
Subject: Re: [PATCH 4/7] x86/kexec: Disable kexec/kdump on platforms with TDX partial write erratum
Date: Wed, 1 Oct 2025 11:00:16 -0700 [thread overview]
Message-ID: <2cbf11a4-fe92-483c-8ab7-182284720700@intel.com> (raw)
In-Reply-To: <CAGtprH_nTBdX-VtMQJM4-y8KcB_F4CnafqpDX7ktASwhO0sxAg@mail.gmail.com>
On 10/1/25 10:17, Vishal Annapurve wrote:
> And also mentions:
> "Also note only the normal kexec needs to worry about this problem, but
> not the crash kexec: 1) The kdump kernel only uses the special memory
> reserved by the first kernel, and the reserved memory can never be used
> by TDX in the first kernel; 2) The /proc/vmcore, which reflects the
> first (crashed) kernel's memory, is only for read. The read will never
> "poison" TDX memory thus cause unexpected machine check (only partial
> write does)."
>
> What was the scenario that led to disabling kdump support altogether
> given the above description?
I think it was purely out of convenience so that the disabling could be
three lines of code.
I don't know off the top of my head if there's a simple enough way to
disable kexec but not kdump. When I applied the thing, I was probably
just considering kexec/kdump a monolithic thing and not thinking that
folks would want one but not the other.
Kai, did you have any other motivations?
next prev parent reply other threads:[~2025-10-01 18:00 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-09-01 16:09 [PATCH v8 0/7] TDX host: kexec/kdump support Paolo Bonzini
2025-09-01 16:09 ` [PATCH 1/7] x86/kexec: Consolidate relocate_kernel() function parameters Paolo Bonzini
2025-09-01 16:09 ` [PATCH 2/7] x86/sme: Use percpu boolean to control WBINVD during kexec Paolo Bonzini
2025-09-01 16:09 ` [PATCH 3/7] x86/virt/tdx: Mark memory cache state incoherent when making SEAMCALL Paolo Bonzini
2025-09-01 16:09 ` [PATCH 4/7] x86/kexec: Disable kexec/kdump on platforms with TDX partial write erratum Paolo Bonzini
2025-09-30 1:38 ` Vishal Annapurve
2025-09-30 21:32 ` Dave Hansen
2025-10-01 2:05 ` Vishal Annapurve
2025-10-01 14:32 ` Dave Hansen
2025-10-01 17:17 ` Vishal Annapurve
2025-10-01 18:00 ` Dave Hansen [this message]
2025-10-01 21:19 ` Huang, Kai
2025-10-02 6:59 ` Reshetova, Elena
2025-10-02 7:46 ` Juergen Gross
2025-10-02 8:10 ` Reshetova, Elena
2025-10-02 15:06 ` Dave Hansen
2025-10-02 16:09 ` Vishal Annapurve
2025-10-18 15:54 ` Vishal Annapurve
2025-10-21 17:08 ` Dave Hansen
2025-10-22 2:50 ` Vishal Annapurve
2025-10-22 21:05 ` Huang, Kai
2025-10-23 16:54 ` Vishal Annapurve
2025-10-07 13:31 ` Jürgen Groß
2025-10-08 15:40 ` Dave Hansen
2025-10-08 18:13 ` Jürgen Groß
2025-10-26 23:33 ` Vishal Annapurve
2025-10-27 0:50 ` Huang, Kai
2025-10-27 16:23 ` Edgecombe, Rick P
2025-10-27 21:28 ` Huang, Kai
2025-10-28 0:07 ` Vishal Annapurve
2025-10-28 9:31 ` Huang, Kai
2025-11-03 16:44 ` Vishal Annapurve
2025-09-01 16:09 ` [PATCH 5/7] x86/virt/tdx: Remove the !KEXEC_CORE dependency Paolo Bonzini
2025-09-01 16:09 ` [PATCH 6/7] x86/virt/tdx: Update the kexec section in the TDX documentation Paolo Bonzini
2025-09-01 16:09 ` [PATCH 7/7] KVM: TDX: Explicitly do WBINVD when no more TDX SEAMCALLs Paolo Bonzini
2025-10-03 13:09 ` [PATCH v8 0/7] TDX host: kexec/kdump support Paolo Bonzini
2025-10-03 13:54 ` David Woodhouse
2025-10-03 14:05 ` Dave Hansen
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