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From: Ard Biesheuvel <ard.biesheuvel@linaro.org>
To: Matthew Garrett <mjg59@google.com>
Cc: Ard Biesheuvel <ardb@kernel.org>,
	linux-efi <linux-efi@vger.kernel.org>,
	Hans de Goede <hdegoede@redhat.com>,
	Ingo Molnar <mingo@kernel.org>, Andy Lutomirski <luto@kernel.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Arvind Sankar <nivedita@alum.mit.edu>
Subject: Re: [PATCH v2 21/21] efi: Allow disabling PCI busmastering on bridges during boot
Date: Fri, 20 Dec 2019 09:06:58 +0200	[thread overview]
Message-ID: <CAKv+Gu9-pcUGmpMVrYd+q+DJNU_737fpqwm5O2-yJJbS5KuGeg@mail.gmail.com> (raw)
In-Reply-To: <CACdnJusxs_vAMvE_tOX12ZJiEc3__1NimT3aD3r-Oabvx62FtA@mail.gmail.com>

On Thu, 19 Dec 2019 at 22:05, Matthew Garrett <mjg59@google.com> wrote:
>
> On Wed, Dec 18, 2019 at 9:03 AM Ard Biesheuvel <ardb@kernel.org> wrote:
> > +       status = efi_call_early(create_event, EVT_SIGNAL_EXIT_BOOT_SERVICES,
> > +                               TPL_CALLBACK, handle_exit_boot_services_event,
> > +                               NULL, &exit_boot_services_event);
> > +       if (status != EFI_SUCCESS) {
> > +               pr_efi_err("Failed to register for EBS() event\n");
> > +               goto free_handle;
> > +       }
>
> OVMF's SEV implementation appears to tear down AMD's IOMMU mappings at
> EVT_SIGNAL_EXIT_BOOT_SERVICES. How are we ensuring that this happens
> first?

It doesn't, and that is kind of the point. The only guarantee you have
is that this runs before ExitBootServices() returns, but after any
other callbacks that have been registered. I know this is not 100%
what you're after, but it is the only way we can avoid poking devices
behind the backs of their drivers.

So this approach is what i am willing to accept for mainline, and I
would even start out by enabling it by default to get the most
coverage. If you need something stronger, I understand but I don't
think it belongs in mainline.

  reply	other threads:[~2019-12-20  7:07 UTC|newest]

Thread overview: 87+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-12-18 17:01 [PATCH v2 00/21] efi/x86: confine type unsafe casting to mixed mode Ard Biesheuvel
2019-12-18 17:01 ` [PATCH v2 01/21] efi/libstub: remove unused __efi_call_early() macro Ard Biesheuvel
2019-12-18 17:01 ` [PATCH v2 02/21] efi/x86: rename efi_is_native() to efi_is_mixed() Ard Biesheuvel
2019-12-18 17:01 ` [PATCH v2 03/21] efi/libstub: use a helper to iterate over a EFI handle array Ard Biesheuvel
2019-12-18 17:01 ` [PATCH v2 04/21] efi/libstub: extend native protocol definitions with mixed_mode aliases Ard Biesheuvel
2019-12-18 17:01 ` [PATCH v2 05/21] efi/libstub: distinguish between native/mixed not 32/64 bit Ard Biesheuvel
2019-12-18 17:01 ` [PATCH v2 06/21] efi/libstub/x86: use mixed mode helpers to populate efi_config Ard Biesheuvel
2019-12-18 17:01 ` [PATCH v2 07/21] efi/libstub: drop explicit 32/64-bit protocol definitions Ard Biesheuvel
2019-12-18 17:01 ` [PATCH v2 08/21] efi/libstub: use stricter typing for firmware function pointers Ard Biesheuvel
2019-12-18 17:01 ` [PATCH v2 09/21] efi/libstub: annotate firmware routines as __efiapi Ard Biesheuvel
2019-12-18 17:01 ` [PATCH v2 10/21] efi/libstub/x86: avoid thunking for native firmware calls Ard Biesheuvel
2019-12-21 21:22   ` Hans de Goede
2019-12-22 12:02     ` Ard Biesheuvel
2019-12-22 12:37       ` Ard Biesheuvel
2019-12-22 12:46       ` Andy Lutomirski
2019-12-22 15:29         ` Ard Biesheuvel
2019-12-22 21:12           ` Arvind Sankar
2019-12-22 21:25             ` Ard Biesheuvel
2019-12-23 11:49       ` Hans de Goede
2019-12-23 12:00         ` Ard Biesheuvel
2019-12-18 17:01 ` [PATCH v2 11/21] efi/libstub: get rid of 'sys_table_arg' macro parameter Ard Biesheuvel
2019-12-18 17:01 ` [PATCH v2 12/21] efi/libstub: unify the efi_char16_printk implementations Ard Biesheuvel
2019-12-18 17:01 ` [PATCH v2 13/21] efi/libstub/x86: drop __efi_early() export of efi_config struct Ard Biesheuvel
2019-12-24 19:34   ` Hans de Goede
2019-12-25 14:42     ` Ard Biesheuvel
2019-12-27 22:44       ` Hans de Goede
2019-12-27 22:51         ` Ard Biesheuvel
2019-12-31 23:04   ` Arvind Sankar
2020-01-01 18:13     ` Ard Biesheuvel
2020-01-01 19:08       ` Arvind Sankar
2020-01-02  7:33         ` Ard Biesheuvel
2020-01-02 14:06           ` Arvind Sankar
2020-01-02 15:20             ` Ard Biesheuvel
2020-01-02 15:51               ` Arvind Sankar
2020-01-02 15:58                 ` Ard Biesheuvel
2020-01-02 16:28                   ` Ard Biesheuvel
2020-01-02 16:59                     ` Ard Biesheuvel
2020-01-02 17:26                       ` Arvind Sankar
2020-01-02 17:30                         ` Ard Biesheuvel
2020-01-02 17:41                           ` Arvind Sankar
2020-01-02 17:48                             ` Ard Biesheuvel
2020-01-02 18:10                               ` Arvind Sankar
2020-01-02 18:38                                 ` Ard Biesheuvel
2020-01-03 14:16                                   ` Arvind Sankar
2020-01-03 14:23                                     ` Ard Biesheuvel
2020-01-02 18:38                               ` Arvind Sankar
2020-01-02 16:59                     ` Arvind Sankar
2020-01-02 17:03                       ` Ard Biesheuvel
2020-01-02 17:21                         ` Arvind Sankar
2019-12-18 17:01 ` [PATCH v2 14/21] efi/libstub: drop sys_table_arg from printk routines Ard Biesheuvel
2019-12-18 17:01 ` [PATCH v2 15/21] efi/libstub: remove 'sys_table_arg' from all function prototypes Ard Biesheuvel
2019-12-18 17:01 ` [PATCH v2 16/21] efi/libstub: drop protocol argument from efi_call_proto() macro Ard Biesheuvel
2019-12-18 17:01 ` [PATCH v2 17/21] efi/libstub: drop 'table' argument from efi_table_attr() macro Ard Biesheuvel
2019-12-18 17:01 ` [PATCH v2 18/21] efi/libstub: use 'func' not 'f' as macro parameter Ard Biesheuvel
2019-12-31 16:51   ` Arvind Sankar
2019-12-31 17:06     ` Ard Biesheuvel
2019-12-31 17:36       ` Arvind Sankar
2019-12-18 17:01 ` [PATCH v2 19/21] efi/libstub: tidy up types and names of global cmdline variables Ard Biesheuvel
2019-12-18 17:01 ` [PATCH v2 20/21] efi/libstub: import type definitions for creating and signalling events Ard Biesheuvel
2019-12-18 17:01 ` [PATCH v2 21/21] efi: Allow disabling PCI busmastering on bridges during boot Ard Biesheuvel
2019-12-19  2:50   ` Andy Lutomirski
2019-12-19 13:17     ` Ard Biesheuvel
2019-12-19 20:04       ` Matthew Garrett
2019-12-19 20:04   ` Matthew Garrett
2019-12-20  7:06     ` Ard Biesheuvel [this message]
2019-12-20  7:17       ` Andy Lutomirski
2019-12-20  8:11         ` Ard Biesheuvel
2019-12-20 19:41           ` Arvind Sankar
2020-01-02 14:46             ` Laszlo Ersek
2020-01-02 15:40               ` Ard Biesheuvel
2019-12-20 20:43       ` Matthew Garrett
2019-12-21 16:44         ` Ard Biesheuvel
2019-12-21 21:24           ` Matthew Garrett
2019-12-21 22:54             ` Arvind Sankar
2019-12-23 14:02               ` Ard Biesheuvel
2019-12-23 15:46                 ` Arvind Sankar
2019-12-23 15:58                   ` Ard Biesheuvel
2019-12-23 16:12                     ` Arvind Sankar
2019-12-23 20:57                   ` Matthew Garrett
2020-02-06 14:30   ` Hans de Goede
2020-02-06 14:35     ` Ard Biesheuvel
2020-03-04 10:38       ` Hans de Goede
2020-03-04 18:26         ` Ard Biesheuvel
2020-03-04 18:49           ` Hans de Goede
2020-03-04 21:59             ` Ard Biesheuvel
2019-12-19 11:12 ` [PATCH v2 00/21] efi/x86: confine type unsafe casting to mixed mode Hans de Goede
2019-12-19 13:22   ` Ard Biesheuvel

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