From: "Huang, Kai" <kai.huang@intel.com>
To: "pbonzini@redhat.com" <pbonzini@redhat.com>,
"Annapurve, Vishal" <vannapurve@google.com>
Cc: "kvm@vger.kernel.org" <kvm@vger.kernel.org>,
"tglx@linutronix.de" <tglx@linutronix.de>,
"Hansen, Dave" <dave.hansen@intel.com>,
"thomas.lendacky@amd.com" <thomas.lendacky@amd.com>,
"ashish.kalra@amd.com" <ashish.kalra@amd.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"Chatre, Reinette" <reinette.chatre@intel.com>,
"dwmw@amazon.co.uk" <dwmw@amazon.co.uk>,
"kas@kernel.org" <kas@kernel.org>,
"mingo@redhat.com" <mingo@redhat.com>,
"Yamahata, Isaku" <isaku.yamahata@intel.com>,
"nik.borisov@suse.com" <nik.borisov@suse.com>,
"seanjc@google.com" <seanjc@google.com>,
"hpa@zytor.com" <hpa@zytor.com>,
"peterz@infradead.org" <peterz@infradead.org>,
"sagis@google.com" <sagis@google.com>,
"Chen, Farrah" <farrah.chen@intel.com>,
"Edgecombe, Rick P" <rick.p.edgecombe@intel.com>,
"bp@alien8.de" <bp@alien8.de>,
"binbin.wu@linux.intel.com" <binbin.wu@linux.intel.com>,
"Gao, Chao" <chao.gao@intel.com>,
"x86@kernel.org" <x86@kernel.org>,
"Williams, Dan J" <dan.j.williams@intel.com>
Subject: Re: [PATCH 4/7] x86/kexec: Disable kexec/kdump on platforms with TDX partial write erratum
Date: Mon, 27 Oct 2025 00:50:42 +0000 [thread overview]
Message-ID: <811dc6c51bb4dfdc19d434f535f8b75d43fde213.camel@intel.com> (raw)
In-Reply-To: <CAGtprH-63eMtsU6TMeYrR8bi=-83sve=ObgdVzSv0htGf-kX+A@mail.gmail.com>
On Sun, 2025-10-26 at 16:33 -0700, Vishal Annapurve wrote:
> > It's feasible to further relax this limitation, i.e., only fail kexec
> > when TDX is actually enabled by the kernel. But this is still a half
> > measure compared to resetting TDX private memory so just do the simplest
> > thing for now.
>
> Hi Kai,
Hi Vishal,
>
> IIUC, kernel doesn't donate any of it's available memory to TDX module
> if TDX is not actually enabled (i.e. if "kvm.intel.tdx=y" kernel
> command line parameter is missing).
Right (for now KVM is the only in-kernel TDX user).
>
> Why is it unsafe to allow kexec/kdump if "kvm.intel.tdx=y" is not
> supplied to the kernel?
It can be relaxed. Please see the above quoted text from the changelog:
> It's feasible to further relax this limitation, i.e., only fail kexec
> when TDX is actually enabled by the kernel. But this is still a half
> measure compared to resetting TDX private memory so just do the simplest
> thing for now.
next prev parent reply other threads:[~2025-10-27 0:50 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
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 [this message]
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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