Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.31 as permitted sender) client-ip=23.128.96.31;
Date:   Mon, 9 Oct 2023 22:13:10 +0800
From:   Baoquan He <bhe@redhat.com>
To:     "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc:     Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
        Dave Hansen <dave.hansen@linux.intel.com>, x86@kernel.org,
        "Rafael J. Wysocki" <rafael@kernel.org>,
        Peter Zijlstra <peterz@infradead.org>,
        Adrian Hunter <adrian.hunter@intel.com>,
        Kuppuswamy Sathyanarayanan 
        <sathyanarayanan.kuppuswamy@linux.intel.com>,
        Elena Reshetova <elena.reshetova@intel.com>,
        Jun Nakajima <jun.nakajima@intel.com>,
        Rick Edgecombe <rick.p.edgecombe@intel.com>,
        Tom Lendacky <thomas.lendacky@amd.com>,
        kexec@lists.infradead.org, linux-coco@lists.linux.dev,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH 00/13] x86/tdx: Add kexec support
Message-ID: <ZSQKdrP9VE96eDxg@MiWiFi-R3L-srv>
References: <20231005131402.14611-1-kirill.shutemov@linux.intel.com>
 <ZSNADxBZEDyxEnZ4@MiWiFi-R3L-srv>
 <20231009133655.3aqi4kwx7wtqgqtm@box.shutemov.name>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20231009133655.3aqi4kwx7wtqgqtm@box.shutemov.name>
Precedence: bulk

On 10/09/23 at 04:36pm, Kirill A. Shutemov wrote:
> On Mon, Oct 09, 2023 at 07:49:35AM +0800, Baoquan He wrote:
> > On 10/05/23 at 04:13pm, Kirill A. Shutemov wrote:
> > > The patchset adds bits and pieces to get kexec (and crashkernel) work on
> > > TDX guest.
> > > 
> > > They bring kexec support to the point when we can start the new kernel,
> > > but it will only be able to use single CPU. It should be enough to cover
> > > the most common case: crashkernel.
> > 
> > Not sure if this question has been raised and answered in the past. Please
> > forgive my bad memory if it has. The one cpu is fine to kdump kernel most
> > of time, while we enable all CPUs by default when kexec rebooting. And kdump
> > kernel with multiple cpu is allowed too. Wondering if there's plan to
> > support the multiple cpu on TDX in the future.
> 
> Sorry, I didn't update this part of cover letter properly, but the last
> patch of the patchset makes possible to kexec with multiple CPUs and the
> 2nd kernel will see them all. It requires support on BIOS side, otherwise
> we fallback to single CPU kexec.

Oops, I didn't read them carefully. You have mentioned that in the last
paragraph of cover letter. That's a great news, thanks.