From: Dave Young <dyoung@redhat.com>
To: Tom Lendacky <thomas.lendacky@amd.com>
Cc: "Konrad Rzeszutek Wilk" <konrad.wilk@oracle.com>,
linux-arch@vger.kernel.org, linux-efi@vger.kernel.org,
kvm@vger.kernel.org, linux-doc@vger.kernel.org, x86@kernel.org,
linux-kernel@vger.kernel.org, kasan-dev@googlegroups.com,
linux-mm@kvack.org, iommu@lists.linux-foundation.org,
"Rik van Riel" <riel@redhat.com>,
"Radim Krčmář" <rkrcmar@redhat.com>,
"Toshimitsu Kani" <toshi.kani@hpe.com>,
"Arnd Bergmann" <arnd@arndb.de>,
"Jonathan Corbet" <corbet@lwn.net>,
"Matt Fleming" <matt@codeblueprint.co.uk>,
"Michael S. Tsirkin" <mst@redhat.com>,
"Joerg Roedel" <joro@8bytes.org>,
"Paolo Bonzini" <pbonzini@redhat.com>,
"Brijesh Singh" <brijesh.singh@amd.com>,
"Ingo Molnar" <mingo@redhat.com>,
"Alexander Potapenko" <glider@google.com>,
"Andy Lutomirski" <luto@kernel.org>,
"H. Peter Anvin" <hpa@zytor.com>,
"Borislav Petkov" <bp@alien8.de>,
"Andrey Ryabinin" <aryabinin@virtuozzo.com>,
"Thomas Gleixner" <tglx@linutronix.de>,
"Larry Woodman" <lwoodman@redhat.com>,
"Dmitry Vyukov" <dvyukov@google.com>
Subject: Re: [RFC PATCH v4 26/28] x86: Allow kexec to be used with SME
Date: Wed, 8 Mar 2017 16:12:28 +0800 [thread overview]
Message-ID: <20170308081228.GD11045@dhcp-128-65.nay.redhat.com> (raw)
In-Reply-To: <998eb58b-eefd-3093-093f-9ae25ddda472@amd.com>
On 03/06/17 at 11:58am, Tom Lendacky wrote:
> On 3/1/2017 3:25 AM, Dave Young wrote:
> > Hi Tom,
>
> Hi Dave,
>
> >
> > On 02/17/17 at 10:43am, Tom Lendacky wrote:
> > > On 2/17/2017 9:57 AM, Konrad Rzeszutek Wilk wrote:
> > > > On Thu, Feb 16, 2017 at 09:47:55AM -0600, Tom Lendacky wrote:
> > > > > Provide support so that kexec can be used to boot a kernel when SME is
> > > > > enabled.
> > > >
> > > > Is the point of kexec and kdump to ehh, dump memory ? But if the
> > > > rest of the memory is encrypted you won't get much, will you?
> > >
> > > Kexec can be used to reboot a system without going back through BIOS.
> > > So you can use kexec without using kdump.
> > >
> > > For kdump, just taking a quick look, the option to enable memory
> > > encryption can be provided on the crash kernel command line and then
> >
> > Is there a simple way to get the SME status? Probably add some sysfs
> > file for this purpose.
>
> Currently there is not. I can look at adding something, maybe just the
> sme_me_mask value, which if non-zero, would indicate SME is active.
>
> >
> > > crash kernel can would be able to copy the memory decrypted if the
> > > pagetable is set up properly. It looks like currently ioremap_cache()
> > > is used to map the old memory page. That might be able to be changed
> > > to a memremap() so that the encryption bit is set in the mapping. That
> > > will mean that memory that is not marked encrypted (EFI tables, swiotlb
> > > memory, etc) would not be read correctly.
> >
> > Manage to store info about those ranges which are not encrypted so that
> > memremap can handle them?
>
> I can look into whether something can be done in this area. Any input
> you can provide as to what would be the best way/place to store the
> range info so kdump can make use of it, would be greatly appreciated.
Previously to support efi runtime in kexec, I passed some efi
infomation via setup_data, see below userspace kexec-tools commit:
e1ffc9e9a0769e1f54185003102e9bec428b84e8, it was what Boris mentioned
about the setup_data use case for kexec.
Suppose you have successfully tested kexec reboot, so the EFI tables you
mentioned should be those area in old mem for copying /proc/vmcore? If
only EFI tables and swiotlb maybe not worth to passing those stuff
across kexec reboot.
I have more idea about this for now..
>
> >
> > >
> > > >
> > > > Would it make sense to include some printk to the user if they
> > > > are setting up kdump that they won't get anything out of it?
> > >
> > > Probably a good idea to add something like that.
> >
> > It will break kdump functionality, it should be fixed instead of
> > just adding printk to warn user..
>
> I do want kdump to work. I'll investigate further what can be done in
> this area.
Thanks a lot!
Dave
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next prev parent reply other threads:[~2017-03-08 8:12 UTC|newest]
Thread overview: 111+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-02-16 15:41 [RFC PATCH v4 00/28] x86: Secure Memory Encryption (AMD) Tom Lendacky
2017-02-16 15:42 ` [RFC PATCH v4 01/28] x86: Documentation for AMD Secure Memory Encryption (SME) Tom Lendacky
[not found] ` <20170216154211.19244.76656.stgit-qCXWGYdRb2BnqfbPTmsdiZQ+2ll4COg0XqFh9Ls21Oc@public.gmane.org>
2017-02-16 17:56 ` Borislav Petkov
2017-02-16 19:48 ` Tom Lendacky
2017-02-16 15:42 ` [RFC PATCH v4 02/28] x86: Set the write-protect cache mode for full PAT support Tom Lendacky
[not found] ` <20170216154225.19244.96438.stgit-qCXWGYdRb2BnqfbPTmsdiZQ+2ll4COg0XqFh9Ls21Oc@public.gmane.org>
2017-02-17 11:07 ` Borislav Petkov
2017-02-17 15:56 ` Tom Lendacky
2017-02-16 15:42 ` [RFC PATCH v4 03/28] x86: Add the Secure Memory Encryption CPU feature Tom Lendacky
[not found] ` <20170216154236.19244.7580.stgit-qCXWGYdRb2BnqfbPTmsdiZQ+2ll4COg0XqFh9Ls21Oc@public.gmane.org>
2017-02-16 18:13 ` Borislav Petkov
2017-02-16 19:42 ` Tom Lendacky
[not found] ` <a1a6a6d7-3aac-3138-1e75-6160f0427a6b-5C7GfCeVMHo@public.gmane.org>
2017-02-16 20:06 ` Borislav Petkov
2017-02-16 15:42 ` [RFC PATCH v4 04/28] x86: Handle reduction in physical address size with SME Tom Lendacky
2017-02-17 11:04 ` Borislav Petkov
2017-02-16 15:43 ` [RFC PATCH v4 05/28] x86: Add Secure Memory Encryption (SME) support Tom Lendacky
2017-02-17 12:00 ` Borislav Petkov
2017-02-25 15:29 ` Borislav Petkov
2017-02-28 23:01 ` Tom Lendacky
2017-02-16 15:43 ` [RFC PATCH v4 06/28] x86: Add support to enable SME during early boot processing Tom Lendacky
[not found] ` <20170216154319.19244.7863.stgit-qCXWGYdRb2BnqfbPTmsdiZQ+2ll4COg0XqFh9Ls21Oc@public.gmane.org>
2017-02-20 12:51 ` Borislav Petkov
2017-02-21 14:55 ` Tom Lendacky
[not found] ` <a23be4fa-d7ef-4e7a-5b6b-73e120a5ca80-5C7GfCeVMHo@public.gmane.org>
2017-02-21 15:10 ` Borislav Petkov
2017-02-16 15:43 ` [RFC PATCH v4 07/28] x86: Provide general kernel support for memory encryption Tom Lendacky
[not found] ` <20170216154332.19244.55451.stgit-qCXWGYdRb2BnqfbPTmsdiZQ+2ll4COg0XqFh9Ls21Oc@public.gmane.org>
2017-02-20 15:21 ` Borislav Petkov
2017-02-21 17:18 ` Tom Lendacky
2017-02-22 12:08 ` Borislav Petkov
2017-02-20 18:38 ` Borislav Petkov
2017-02-22 16:43 ` Tom Lendacky
2017-02-22 18:13 ` Dave Hansen
2017-02-23 23:12 ` Tom Lendacky
2017-02-22 18:13 ` Dave Hansen
2017-02-16 15:43 ` [RFC PATCH v4 08/28] x86: Extend the early_memremap support with additional attrs Tom Lendacky
[not found] ` <20170216154348.19244.11884.stgit-qCXWGYdRb2BnqfbPTmsdiZQ+2ll4COg0XqFh9Ls21Oc@public.gmane.org>
2017-02-20 15:43 ` Borislav Petkov
2017-02-22 15:42 ` Tom Lendacky
2017-02-16 15:43 ` [RFC PATCH v4 09/28] x86: Add support for early encryption/decryption of memory Tom Lendacky
[not found] ` <20170216154358.19244.6082.stgit-qCXWGYdRb2BnqfbPTmsdiZQ+2ll4COg0XqFh9Ls21Oc@public.gmane.org>
2017-02-20 18:22 ` Borislav Petkov
2017-02-22 15:48 ` Tom Lendacky
2017-02-16 15:44 ` [RFC PATCH v4 10/28] x86: Insure that boot memory areas are mapped properly Tom Lendacky
[not found] ` <20170216154411.19244.99258.stgit-qCXWGYdRb2BnqfbPTmsdiZQ+2ll4COg0XqFh9Ls21Oc@public.gmane.org>
2017-02-20 19:45 ` Borislav Petkov
2017-02-22 18:34 ` Tom Lendacky
2017-02-16 15:44 ` [RFC PATCH v4 11/28] x86: Add support to determine the E820 type of an address Tom Lendacky
[not found] ` <20170216154430.19244.95519.stgit-qCXWGYdRb2BnqfbPTmsdiZQ+2ll4COg0XqFh9Ls21Oc@public.gmane.org>
2017-02-20 20:09 ` Borislav Petkov
2017-02-28 22:34 ` Tom Lendacky
2017-03-03 9:52 ` Borislav Petkov
2017-02-16 15:44 ` [RFC PATCH v4 12/28] efi: Add an EFI table address match function Tom Lendacky
2017-02-16 15:44 ` [RFC PATCH v4 13/28] efi: Update efi_mem_type() to return defined EFI mem types Tom Lendacky
2017-02-21 12:05 ` Matt Fleming
2017-02-23 17:27 ` Tom Lendacky
2017-02-24 9:57 ` Matt Fleming
2017-02-16 15:45 ` [RFC PATCH v4 14/28] Add support to access boot related data in the clear Tom Lendacky
[not found] ` <20170216154508.19244.58580.stgit-qCXWGYdRb2BnqfbPTmsdiZQ+2ll4COg0XqFh9Ls21Oc@public.gmane.org>
2017-02-21 15:06 ` Borislav Petkov
2017-02-23 21:34 ` Tom Lendacky
2017-02-24 10:21 ` Borislav Petkov
2017-02-24 15:04 ` Tom Lendacky
2017-02-24 15:22 ` Borislav Petkov
2017-03-08 6:55 ` Dave Young
2017-03-17 19:50 ` Tom Lendacky
2017-02-16 15:45 ` [RFC PATCH v4 15/28] Add support to access persistent memory " Tom Lendacky
2017-03-17 22:58 ` Elliott, Robert (Persistent Memory)
2017-03-23 21:02 ` Tom Lendacky
2017-02-16 15:45 ` [RFC PATCH v4 16/28] x86: Add support for changing memory encryption attribute Tom Lendacky
2017-02-22 18:52 ` Borislav Petkov
2017-02-28 22:46 ` Tom Lendacky
2017-02-16 15:45 ` [RFC PATCH v4 17/28] x86: Decrypt trampoline area if memory encryption is active Tom Lendacky
2017-02-16 15:46 ` [RFC PATCH v4 18/28] x86: DMA support for memory encryption Tom Lendacky
2017-02-25 17:10 ` Borislav Petkov
2017-03-06 17:47 ` Tom Lendacky
2017-02-16 15:46 ` [RFC PATCH v4 19/28] swiotlb: Add warnings for use of bounce buffers with SME Tom Lendacky
2017-02-17 15:59 ` Konrad Rzeszutek Wilk
2017-02-17 16:51 ` Tom Lendacky
2017-03-02 17:01 ` Paolo Bonzini
2017-02-27 17:52 ` Borislav Petkov
2017-02-28 23:19 ` Tom Lendacky
2017-03-01 11:17 ` Borislav Petkov
2017-02-16 15:46 ` [RFC PATCH v4 20/28] iommu/amd: Disable AMD IOMMU if memory encryption is active Tom Lendacky
2017-02-16 15:46 ` [RFC PATCH v4 21/28] x86: Check for memory encryption on the APs Tom Lendacky
[not found] ` <20170216154647.19244.18733.stgit-qCXWGYdRb2BnqfbPTmsdiZQ+2ll4COg0XqFh9Ls21Oc@public.gmane.org>
2017-02-27 18:17 ` Borislav Petkov
2017-02-28 23:28 ` Tom Lendacky
[not found] ` <5f461d57-9232-1cb3-d4d9-9b8a39d00b12-5C7GfCeVMHo@public.gmane.org>
2017-03-01 11:17 ` Borislav Petkov
2017-02-16 15:47 ` [RFC PATCH v4 22/28] x86: Do not specify encrypted memory for video mappings Tom Lendacky
2017-02-16 15:47 ` [RFC PATCH v4 23/28] x86/kvm: Enable Secure Memory Encryption of nested page tables Tom Lendacky
2017-02-16 15:47 ` [RFC PATCH v4 24/28] x86: Access the setup data through debugfs decrypted Tom Lendacky
2017-03-08 7:04 ` Dave Young
2017-03-17 19:54 ` Tom Lendacky
2017-02-16 15:47 ` [RFC PATCH v4 25/28] x86: Access the setup data through sysfs decrypted Tom Lendacky
2017-03-08 7:09 ` Dave Young
2017-03-17 20:09 ` Tom Lendacky
2017-02-16 15:47 ` [RFC PATCH v4 26/28] x86: Allow kexec to be used with SME Tom Lendacky
2017-02-17 15:57 ` Konrad Rzeszutek Wilk
2017-02-17 16:43 ` Tom Lendacky
2017-03-01 9:25 ` Dave Young
2017-03-01 9:27 ` Dave Young
2017-03-06 17:58 ` Tom Lendacky
2017-03-06 18:04 ` Tom Lendacky
2017-03-08 8:12 ` Dave Young [this message]
2017-02-28 10:35 ` Borislav Petkov
2017-03-01 15:36 ` Tom Lendacky
2017-02-16 15:48 ` [RFC PATCH v4 27/28] x86: Add support to encrypt the kernel in-place Tom Lendacky
[not found] ` <20170216154808.19244.475.stgit-qCXWGYdRb2BnqfbPTmsdiZQ+2ll4COg0XqFh9Ls21Oc@public.gmane.org>
2017-03-01 17:36 ` Borislav Petkov
2017-03-02 18:30 ` Tom Lendacky
2017-03-02 18:51 ` Borislav Petkov
2017-02-16 15:48 ` [RFC PATCH v4 28/28] x86: Add support to make use of Secure Memory Encryption Tom Lendacky
2017-03-01 18:40 ` Borislav Petkov
2017-03-07 16:05 ` Tom Lendacky
2017-03-07 17:42 ` Borislav Petkov
2017-03-08 15:05 ` Borislav Petkov
[not found] ` <20170216154158.19244.66630.stgit-qCXWGYdRb2BnqfbPTmsdiZQ+2ll4COg0XqFh9Ls21Oc@public.gmane.org>
2017-02-18 18:12 ` [RFC PATCH v4 00/28] x86: Secure Memory Encryption (AMD) Borislav Petkov
2017-02-21 15:09 ` Tom Lendacky
2017-02-21 17:42 ` Rik van Riel
[not found] ` <1487698965.17158.8.camel-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2017-02-21 17:53 ` Borislav Petkov
2017-03-01 9:17 ` Dave Young
2017-03-01 17:51 ` Tom Lendacky
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