public inbox for linux-kernel@vger.kernel.org
 help / color / mirror / Atom feed
From: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
To: Tom Lendacky <thomas.lendacky@amd.com>
Cc: tglx@linutronix.de, mingo@redhat.com, bp@alien8.de,
	dave.hansen@intel.com, luto@kernel.org, peterz@infradead.org,
	sathyanarayanan.kuppuswamy@linux.intel.com, aarcange@redhat.com,
	ak@linux.intel.com, dan.j.williams@intel.com, david@redhat.com,
	hpa@zytor.com, jgross@suse.com, jmattson@google.com,
	joro@8bytes.org, jpoimboe@redhat.com, knsathya@kernel.org,
	pbonzini@redhat.com, sdeep@vmware.com, seanjc@google.com,
	tony.luck@intel.com, vkuznets@redhat.com, wanpengli@tencent.com,
	x86@kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCHv3 16/32] x86/boot: Allow to hook up alternative port I/O helpers
Date: Tue, 22 Feb 2022 01:02:33 +0300	[thread overview]
Message-ID: <20220221220233.mbntv342fg2wp7dp@black.fi.intel.com> (raw)
In-Reply-To: <8bb2e660-f92d-a501-57ea-61138dafed28@amd.com>

On Mon, Feb 21, 2022 at 02:04:33PM -0600, Tom Lendacky wrote:
> On 2/18/22 10:17, Kirill A. Shutemov wrote:
> > Port I/O instructions trigger #VE in the TDX environment. In response to
> > the exception, kernel emulates these instructions using hypercalls.
> > 
> > But during early boot, on the decompression stage, it is cumbersome to
> > deal with #VE. It is cleaner to go to hypercalls directly, bypassing #VE
> > handling.
> > 
> > Add a way to hook up alternative port I/O helpers in the boot stub.
> 
> This seems like a lot of churn in order to get this all working without
> taking a #VE.

Well, it evolved from more concise (but also more hacky) implementation:

https://lore.kernel.org/all/20211214150304.62613-11-kirill.shutemov@linux.intel.com

> How cumbersome is it to get #VE handling working in the decompression
> stage? Can you build on any of the support that was added to handle #VC?

We definitely can.

But I still think exception-based implementation is inherently more
fragile. I would rather stick with this.

-- 
 Kirill A. Shutemov

  reply	other threads:[~2022-02-21 22:02 UTC|newest]

Thread overview: 71+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-02-18 16:16 [PATCHv3 00/32] TDX Guest: TDX core support Kirill A. Shutemov
2022-02-18 16:16 ` [PATCHv3 01/32] x86/mm: Fix warning on build with X86_MEM_ENCRYPT=y Kirill A. Shutemov
2022-02-18 19:39   ` Dave Hansen
2022-02-18 16:16 ` [PATCHv3 02/32] x86/coco: Add API to handle encryption mask Kirill A. Shutemov
2022-02-18 20:36   ` Dave Hansen
2022-02-18 21:33     ` Kirill A. Shutemov
2022-02-18 21:58       ` Borislav Petkov
2022-02-19  0:13         ` [PATCHv3.1 2/32] x86/coco: Explicitly declare type of confidential computing platform Kirill A. Shutemov
2022-02-19  0:13           ` [PATCHv3.1 2.1/2] x86/coco: Add API to handle encryption mask Kirill A. Shutemov
2022-02-21 18:31             ` Tom Lendacky
2022-02-21 22:14               ` Kirill A. Shutemov
2022-02-21 21:05             ` Borislav Petkov
2022-02-21 22:10               ` Kirill A. Shutemov
2022-02-21 22:36                 ` Borislav Petkov
2022-02-21 23:25                   ` Kirill A. Shutemov
2022-02-22 13:31                     ` Borislav Petkov
2022-02-21 11:07           ` [PATCHv3.1 2/32] x86/coco: Explicitly declare type of confidential computing platform Borislav Petkov
2022-02-21 11:44             ` Kirill A. Shutemov
2022-02-21 12:05               ` Borislav Petkov
2022-02-21 13:52             ` Wei Liu
2022-02-21 20:20               ` Borislav Petkov
2022-02-21 19:28       ` [PATCHv3 02/32] x86/coco: Add API to handle encryption mask Dave Hansen
2022-02-21 19:49         ` Borislav Petkov
2022-02-21 22:21           ` Kirill A. Shutemov
2022-02-21 22:56             ` Borislav Petkov
2022-02-21 23:18               ` Kirill A. Shutemov
2022-02-22 13:28                 ` Borislav Petkov
2022-02-21 22:28         ` Kirill A. Shutemov
2022-02-22 11:03           ` Kirill A. Shutemov
2022-02-22 13:37             ` Borislav Petkov
2022-02-22 13:52               ` Kirill A. Shutemov
2022-02-18 16:16 ` [PATCHv3 03/32] x86/tdx: Detect running as a TDX guest in early boot Kirill A. Shutemov
2022-02-18 21:07   ` Dave Hansen
2022-02-20 15:01     ` Kirill A. Shutemov
2022-02-18 16:16 ` [PATCHv3 04/32] x86/tdx: Provide common base for SEAMCALL and TDCALL C wrappers Kirill A. Shutemov
2022-02-18 16:16 ` [PATCHv3 05/32] x86/tdx: Add __tdx_module_call() and __tdx_hypercall() helper functions Kirill A. Shutemov
2022-02-18 16:16 ` [PATCHv3 06/32] x86/tdx: Extend the confidential computing API to support TDX guests Kirill A. Shutemov
2022-02-18 16:16 ` [PATCHv3 07/32] x86/tdx: Exclude shared bit from __PHYSICAL_MASK Kirill A. Shutemov
2022-02-18 16:16 ` [PATCHv3 08/32] x86/traps: Add #VE support for TDX guest Kirill A. Shutemov
2022-02-22  7:19   ` Dingji Li
2022-02-22 11:11     ` Kirill A. Shutemov
2022-02-18 16:16 ` [PATCHv3 09/32] x86/tdx: Add HLT support for TDX guests Kirill A. Shutemov
2022-02-18 16:16 ` [PATCHv3 10/32] x86/tdx: Add MSR " Kirill A. Shutemov
2022-02-18 16:16 ` [PATCHv3 11/32] x86/tdx: Handle CPUID via #VE Kirill A. Shutemov
2022-02-18 16:16 ` [PATCHv3 12/32] x86/tdx: Handle in-kernel MMIO Kirill A. Shutemov
2022-02-18 16:16 ` [PATCHv3 13/32] x86/tdx: Detect TDX at early kernel decompression time Kirill A. Shutemov
2022-02-21 11:37   ` Cyrill Gorcunov
2022-02-21 13:53     ` Kirill A. Shutemov
2022-02-18 16:17 ` [PATCHv3 14/32] x86: Adjust types used in port I/O helpers Kirill A. Shutemov
2022-02-18 16:17 ` [PATCHv3 15/32] x86: Consolidate " Kirill A. Shutemov
2022-02-18 16:17 ` [PATCHv3 16/32] x86/boot: Allow to hook up alternative " Kirill A. Shutemov
2022-02-21 20:04   ` Tom Lendacky
2022-02-21 22:02     ` Kirill A. Shutemov [this message]
2022-02-22  1:25       ` Josh Poimboeuf
2022-02-18 16:17 ` [PATCHv3 17/32] x86/boot/compressed: Support TDX guest port I/O at decompression time Kirill A. Shutemov
2022-02-18 16:17 ` [PATCHv3 18/32] x86/tdx: Add port I/O emulation Kirill A. Shutemov
2022-02-18 16:17 ` [PATCHv3 19/32] x86/tdx: Handle early boot port I/O Kirill A. Shutemov
2022-02-18 16:17 ` [PATCHv3 20/32] x86/tdx: Wire up KVM hypercalls Kirill A. Shutemov
2022-02-18 16:17 ` [PATCHv3 21/32] x86/boot: Add a trampoline for booting APs via firmware handoff Kirill A. Shutemov
2022-02-18 16:17 ` [PATCHv3 22/32] x86/acpi, x86/boot: Add multiprocessor wake-up support Kirill A. Shutemov
2022-02-18 16:17 ` [PATCHv3 23/32] x86/boot: Set CR0.NE early and keep it set during the boot Kirill A. Shutemov
2022-02-18 16:17 ` [PATCHv3 24/32] x86/boot: Avoid #VE during boot for TDX platforms Kirill A. Shutemov
2022-02-18 16:17 ` [PATCHv3 25/32] x86/topology: Disable CPU online/offline control for TDX guests Kirill A. Shutemov
2022-02-18 16:17 ` [PATCHv3 26/32] x86/tdx: Make pages shared in ioremap() Kirill A. Shutemov
2022-02-18 16:17 ` [PATCHv3 27/32] x86/mm/cpa: Generailize __set_memory_enc_pgtable() Kirill A. Shutemov
2022-02-21 15:46   ` Brijesh Singh
2022-02-18 16:17 ` [PATCHv3 28/32] x86/mm/cpa: Add support for TDX shared memory Kirill A. Shutemov
2022-02-18 16:17 ` [PATCHv3 29/32] x86/kvm: Use bounce buffers for TD guest Kirill A. Shutemov
2022-02-18 16:17 ` [PATCHv3 30/32] x86/tdx: ioapic: Add shared bit for IOAPIC base address Kirill A. Shutemov
2022-02-18 16:17 ` [PATCHv3 31/32] ACPICA: Avoid cache flush on TDX guest Kirill A. Shutemov
2022-02-18 16:17 ` [PATCHv3 32/32] Documentation/x86: Document TDX kernel architecture 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=20220221220233.mbntv342fg2wp7dp@black.fi.intel.com \
    --to=kirill.shutemov@linux.intel.com \
    --cc=aarcange@redhat.com \
    --cc=ak@linux.intel.com \
    --cc=bp@alien8.de \
    --cc=dan.j.williams@intel.com \
    --cc=dave.hansen@intel.com \
    --cc=david@redhat.com \
    --cc=hpa@zytor.com \
    --cc=jgross@suse.com \
    --cc=jmattson@google.com \
    --cc=joro@8bytes.org \
    --cc=jpoimboe@redhat.com \
    --cc=knsathya@kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=luto@kernel.org \
    --cc=mingo@redhat.com \
    --cc=pbonzini@redhat.com \
    --cc=peterz@infradead.org \
    --cc=sathyanarayanan.kuppuswamy@linux.intel.com \
    --cc=sdeep@vmware.com \
    --cc=seanjc@google.com \
    --cc=tglx@linutronix.de \
    --cc=thomas.lendacky@amd.com \
    --cc=tony.luck@intel.com \
    --cc=vkuznets@redhat.com \
    --cc=wanpengli@tencent.com \
    --cc=x86@kernel.org \
    /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