From: lijiang <lijiang@redhat.com>
To: Borislav Petkov <bp@alien8.de>
Cc: linux-kernel@vger.kernel.org, mingo@redhat.com,
tglx@linutronix.de, hpa@zytor.com, ebiederm@xmission.com,
joro@8bytes.org, thomas.lendacky@amd.com, dyoung@redhat.com,
kexec@lists.infradead.org, iommu@lists.linux-foundation.org,
bhe@redhat.com
Subject: Re: [PATCH 1/5 V5] Add a function(ioremap_encrypted) for kdump when AMD sme enabled
Date: Tue, 3 Jul 2018 19:25:21 +0800 [thread overview]
Message-ID: <55b86851-4978-9289-8a1f-012c6114ec9e@redhat.com> (raw)
In-Reply-To: <20180703093924.GA5748@zn.tnic>
在 2018年07月03日 17:39, Borislav Petkov 写道:
> On Tue, Jul 03, 2018 at 10:17:19AM +0800, lijiang wrote:
>> for example, the elfcorehdr. In fact, the elfcorehdr and notes
>
> You mean this?
>
> ssize_t __weak elfcorehdr_read_notes(char *buf, size_t count, u64 *ppos)
> {
> - return read_from_oldmem(buf, count, ppos, 0);
> + return read_from_oldmem(buf, count, ppos, 0, sme_active());
>
> That looks encrypted to me.
>
The elf notes is an old memory, it is encrypted.
But the elf header is a crash kernel reserved memory, which is unencrypted.
ssize_t __weak elfcorehdr_read(char *buf, size_t count, u64 *ppos)
{
- return read_from_oldmem(buf, count, ppos, 0);
+ return read_from_oldmem(buf, count, ppos, 0, false);
}
They call the same function(read_from_oldmem->ioremap_cache), so it is hard to
properly remap the memory if we don't use the parameter to distinguish.
Regards,
Lianbo
>> call the same function(read_from_oldmem->ioremap_cache), in this case,
>> it is very difficult to properly remap the memory if the caller don't
>> care whether the memory is encrypted.
>
> So beef up the logic in __ioremap_caller() to figure out based on the
> address whether to access the memory encrypted or not. You can find out
> the elfcorehdr address in the capture kernel.
>
next prev parent reply other threads:[~2018-07-03 11:25 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-07-02 7:26 [PATCH 0/5 V5] Support kdump for AMD secure memory encryption(SME) Lianbo Jiang
2018-07-02 7:26 ` [PATCH 1/5 V5] Add a function(ioremap_encrypted) for kdump when AMD sme enabled Lianbo Jiang
2018-07-02 10:14 ` Borislav Petkov
2018-07-03 2:17 ` lijiang
2018-07-03 9:39 ` Borislav Petkov
2018-07-03 11:25 ` lijiang [this message]
2018-07-03 10:58 ` lijiang
2018-07-03 11:14 ` Borislav Petkov
2018-07-03 11:44 ` lijiang
2018-07-09 6:28 ` lijiang
2018-07-09 9:29 ` Borislav Petkov
2018-07-09 13:55 ` lijiang
2018-07-13 17:08 ` Borislav Petkov
2018-07-20 5:06 ` lijiang
2018-07-20 5:23 ` Dave Young
2018-07-20 7:32 ` Borislav Petkov
2018-07-20 9:55 ` lijiang
2018-07-20 10:08 ` Boris Petkov
2018-08-16 5:35 ` lijiang
2018-08-23 15:21 ` Borislav Petkov
2018-07-02 7:26 ` [PATCH 2/5 V5] Allocate pages for kdump without encryption when SME is enabled Lianbo Jiang
2018-07-02 7:26 ` [PATCH 3/5 V5] Remap the device table of IOMMU in encrypted manner for kdump Lianbo Jiang
2018-07-02 7:26 ` [PATCH 4/5 V5] Adjust some permanent mappings in unencrypted ways for kdump when SME is enabled Lianbo Jiang
2018-07-02 7:26 ` [PATCH 5/5 V5] Help to dump the old memory encrypted into vmcore file Lianbo Jiang
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=55b86851-4978-9289-8a1f-012c6114ec9e@redhat.com \
--to=lijiang@redhat.com \
--cc=bhe@redhat.com \
--cc=bp@alien8.de \
--cc=dyoung@redhat.com \
--cc=ebiederm@xmission.com \
--cc=hpa@zytor.com \
--cc=iommu@lists.linux-foundation.org \
--cc=joro@8bytes.org \
--cc=kexec@lists.infradead.org \
--cc=linux-kernel@vger.kernel.org \
--cc=mingo@redhat.com \
--cc=tglx@linutronix.de \
--cc=thomas.lendacky@amd.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 NNTP newsgroup(s).