From: David Hildenbrand <david@redhat.com>
To: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>,
Borislav Petkov <bp@alien8.de>,
Andrew Morton <akpm@linux-foundation.org>,
Dave Hansen <dave.hansen@intel.com>,
Vlastimil Babka <vbabka@suse.cz>,
Mike Rapoport <rppt@linux.ibm.com>,
Lorenzo Stoakes <lstoakes@gmail.com>,
Tom Lendacky <thomas.lendacky@amd.com>,
Baoquan He <bhe@redhat.com>, Vivek Goyal <vgoyal@redhat.com>,
Dave Young <dyoung@redhat.com>,
linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
linux-mm@kvack.org, linux-coco@lists.linux.dev,
linux-efi@vger.kernel.org, kexec@lists.infradead.org
Subject: Re: [PATCH 1/3] proc/vmcore: Do not map unaccepted memory
Date: Mon, 11 Sep 2023 16:33:48 +0200 [thread overview]
Message-ID: <f05056e6-77a7-d0f5-615e-36efaab3ff05@redhat.com> (raw)
In-Reply-To: <20230911100555.mjjnx3ujnjlaxgsy@box.shutemov.name>
On 11.09.23 12:05, Kirill A. Shutemov wrote:
> On Mon, Sep 11, 2023 at 11:50:31AM +0200, David Hildenbrand wrote:
>> On 11.09.23 11:27, Kirill A. Shutemov wrote:
>>> On Mon, Sep 11, 2023 at 10:42:51AM +0200, David Hildenbrand wrote:
>>>> On 11.09.23 10:41, Kirill A. Shutemov wrote:
>>>>> On Mon, Sep 11, 2023 at 10:03:36AM +0200, David Hildenbrand wrote:
>>>>>> On 06.09.23 09:39, Adrian Hunter wrote:
>>>>>>> Support for unaccepted memory was added recently, refer commit
>>>>>>> dcdfdd40fa82 ("mm: Add support for unaccepted memory"), whereby
>>>>>>> a virtual machine may need to accept memory before it can be used.
>>>>>>>
>>>>>>> Do not map unaccepted memory because it can cause the guest to fail.
>>>>>>>
>>>>>>> For /proc/vmcore, which is read-only, this means a read or mmap of
>>>>>>> unaccepted memory will return zeros.
>>>>>>
>>>>>> Does a second (kdump) kernel that exposes /proc/vmcore reliably get access
>>>>>> to the information whether memory of the first kernel is unaccepted (IOW,
>>>>>> not its memory, but the memory of the first kernel it is supposed to expose
>>>>>> via /proc/vmcore)?
>>>>>
>>>>> There are few patches in my queue to few related issue, but generally,
>>>>> yes, the information is available to the target kernel via EFI
>>>>> configuration table.
>>>>
>>>> I assume that table provided by the first kernel, and not read directly from
>>>> HW, correct?
>>>
>>> The table is constructed by the EFI stub in the first kernel based on EFI
>>> memory map.
>>>
>>
>> Okay, should work then once that's done by the first kernel.
>>
>> Maybe include this patch in your series?
>
> Can do. But the other two patches are not related to kexec. Hm.
Yes, the others can go in separately. But this here really needs other
kexec/kdump changes.
--
Cheers,
David / dhildenb
next prev parent reply other threads:[~2023-09-11 14:33 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-09-06 7:38 [PATCH 0/3] Do not map unaccepted memory Adrian Hunter
2023-09-06 7:39 ` [PATCH 1/3] proc/vmcore: " Adrian Hunter
2023-09-07 15:39 ` Dave Hansen
2023-09-07 15:44 ` Adrian Hunter
2023-09-07 15:51 ` Dave Hansen
2023-09-11 8:03 ` David Hildenbrand
2023-09-11 8:41 ` Kirill A. Shutemov
2023-09-11 8:42 ` David Hildenbrand
2023-09-11 9:27 ` Kirill A. Shutemov
2023-09-11 9:50 ` David Hildenbrand
2023-09-11 10:05 ` Kirill A. Shutemov
2023-09-11 14:33 ` David Hildenbrand [this message]
2023-09-06 7:39 ` [PATCH 2/3] proc/kcore: " Adrian Hunter
2023-09-07 15:36 ` Dave Hansen
2023-09-07 15:43 ` Dave Hansen
2023-09-06 7:39 ` [PATCH 3/3] /dev/mem: " Adrian Hunter
2023-09-07 10:06 ` Kirill A. Shutemov
2023-09-07 14:15 ` Dave Hansen
2023-09-07 14:25 ` Kirill A. Shutemov
2023-09-07 14:46 ` Dave Hansen
2023-09-07 15:04 ` Dave Hansen
2023-09-11 8:09 ` David Hildenbrand
2023-09-11 14:32 ` Dave Hansen
2023-09-07 10:07 ` [PATCH 0/3] " Kirill A. Shutemov
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=f05056e6-77a7-d0f5-615e-36efaab3ff05@redhat.com \
--to=david@redhat.com \
--cc=adrian.hunter@intel.com \
--cc=akpm@linux-foundation.org \
--cc=bhe@redhat.com \
--cc=bp@alien8.de \
--cc=dave.hansen@intel.com \
--cc=dyoung@redhat.com \
--cc=kexec@lists.infradead.org \
--cc=kirill.shutemov@linux.intel.com \
--cc=linux-coco@lists.linux.dev \
--cc=linux-efi@vger.kernel.org \
--cc=linux-fsdevel@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=lstoakes@gmail.com \
--cc=rppt@linux.ibm.com \
--cc=thomas.lendacky@amd.com \
--cc=vbabka@suse.cz \
--cc=vgoyal@redhat.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
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 read-only IMAP folder(s) and NNTP newsgroup(s).