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From: Dave Young <dyoung@redhat.com>
To: Junichi Nomura <j-nomura@ce.jp.nec.com>
Cc: "fanc.fnst@cn.fujitsu.com" <fanc.fnst@cn.fujitsu.com>,
	"x86@kernel.org" <x86@kernel.org>,
	"kexec@lists.infradead.org" <kexec@lists.infradead.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	Borislav Petkov <bp@alien8.de>, "bp@suse.de" <bp@suse.de>
Subject: Re: [PATCH] x86/boot: Use EFI setup data if provided
Date: Mon, 25 Mar 2019 14:59:21 +0800
Message-ID: <20190325065921.GA11096@dhcp-128-65.nay.redhat.com> (raw)
In-Reply-To: <bcb5bd29-a3b8-e42d-8da7-a8501f695c21@ce.jp.nec.com>

On 03/25/19 at 06:47am, Junichi Nomura wrote:
> On 3/25/19 3:19 PM, Dave Young wrote:
> > On 03/25/19 at 02:01pm, Dave Young wrote:
> >> On 03/25/19 at 12:27am, Junichi Nomura wrote:
> >>> On Fri, Mar 22, 2019 at 04:23:28PM +0100, Borislav Petkov wrote:
> >>>> On Fri, Mar 22, 2019 at 11:03:43AM +0000, Junichi Nomura wrote:
> >>>>> Commit 3a63f70bf4c3a ("x86/boot: Early parse RSDP and save it in
> >>>>> boot_params") broke kexec boot on EFI systems.  efi_get_rsdp_addr()
> >>>>> in the early parsing code tries to search RSDP from EFI table but
> >>>>> whose address is virtual.
> >>>>>
> >>>>> Since kexec(1) provides physical address of config_table via boot_params,
> >>>>> efi_get_rsdp_addr() should look for setup_data in the same way as
> >>>>> efi_systab_init() in arch/x86/platform/efi/efi.c does.
> >>>>
> >>>> If the kexec kernel should continue to use efi_systab_init() then you
> >>>> should make efi_get_rsdp_addr() exit early in the kexec-ed kernel.
> >>>
> >>> I'm not sure which way kexec devel is going. Added kexec list.
> >>> Here is the version that exits early in efi_get_rsdp_addr().
> >>>
> >>> [PATCH] x86/boot: Don't try to search RSDP from EFI when kexec-booted
> >>>
> >>> Commit 3a63f70bf4c3a ("x86/boot: Early parse RSDP and save it in
> >>> boot_params") broke kexec boot on EFI systems.  efi_get_rsdp_addr()
> >>> in the early parsing code tries to search RSDP from EFI table but
> >>> whose address is virtual.
> >>>
> >>> Normally kexec(1) provides physical address of config_table via boot_params
> >>> and EFI code uses that during initialization.
> >>> For the early boot code, we just exit efi_get_rsdp_addr() early if the kernel
> >>> is booted by kexec.
> >>>
> >>> Fixes: 3a63f70bf4c3a ("x86/boot: Early parse RSDP and save it in boot_params")
> >>> Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com>
> >>> Cc: Chao Fan <fanc.fnst@cn.fujitsu.com>
> >>> Cc: Borislav Petkov <bp@suse.de>
> >>>
> >>> diff --git a/arch/x86/boot/compressed/acpi.c b/arch/x86/boot/compressed/acpi.c
> >>> index 0ef4ad5..1cefc43 100644
> >>> --- a/arch/x86/boot/compressed/acpi.c
> >>> +++ b/arch/x86/boot/compressed/acpi.c
> >>> @@ -44,6 +44,24 @@ static acpi_physical_address get_acpi_rsdp(void)
> >>>  	return addr;
> >>>  }
> >>>  
> >>> +static bool is_kexec_booted(void)
> >>> +{
> >>> +	struct setup_data *data;
> >>> +
> >>> +	/*
> >>> +	 * kexec-tools provides EFI setup data so that kexec-ed kernel
> >>> +	 * can find proper tables.
> >>> +	 */
> >>> +	data = (struct setup_data *) boot_params->hdr.setup_data;
> >>> +	while (data) {
> >>> +		if (data->type == SETUP_EFI)
> >>> +			return true;
> >>> +		data = (struct setup_data *) data->next;
> >>> +	}
> >>> +
> >>> +	return false;
> >>> +}
> >>> +
> >>>  /* Search EFI system tables for RSDP. */
> >>>  static acpi_physical_address efi_get_rsdp_addr(void)
> >>>  {
> >>> @@ -57,6 +75,10 @@ static acpi_physical_address efi_get_rsdp_addr(void)
> >>>  	int size, i;
> >>>  	char *sig;
> >>>  
> >>> +	/* If the system is kexec-booted, poking EFI systab may not work. */
> >>> +	if (is_kexec_booted())
> >>> +		return 0;
> >>> +
> >>>  	ei = &boot_params->efi_info;
> >>>  	sig = (char *)&ei->efi_loader_signature;
> >>>  
> >>>
> >>> _______________________________________________
> >>> kexec mailing list
> >>> kexec@lists.infradead.org
> >>> http://lists.infradead.org/mailman/listinfo/kexec
> >>
> >> Good catch, this way looks good to me.  But the function
> >> is_kexec_booted can be compiled when #ifdef CONFIG_EFI
> >>
> >> Otherwise:
> >>
> >> Acked-by: Dave Young <dyoung@redhat.com>
> >>
> > 
> > Hold on, I replied too quick.  One question is does the above patch
> > passed your test?   It can workaround and skip the wrong phys addr
> > issue, but the acpi early parsing still fails because efi_get_rsdp_addr
> > return 0? 
> 
> The patch works for me.
> Early parsing fails with the 2nd patch but it boots fine.
> EFI initialization is done later without boot_params->acpi_rsdp_addr.
> I think that's how v5.0 and earlier kernels work.

Ok, thanks 

> 
> > If this is the case you may need go with your old patch.
> > 
> > I think normally people do not see this bug, because kernel will set the
> > rsdp in boot_params->acpi_rsdp_addr.  Maybe you are testing with
> 
> I think it's only done for file-based kexec interface.

Saw Kairui's another reply, yes, kexec-tools need a patch to fill the
value as well then.

I would vote for a repost of your old patch with some #ifdef

Thanks
Dave

  reply index

Thread overview: 90+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-03-22 11:03 Junichi Nomura
2019-03-22 15:23 ` Borislav Petkov
2019-03-25  0:27   ` Junichi Nomura
2019-03-25  6:01     ` Dave Young
2019-03-25  6:19       ` Dave Young
2019-03-25  6:45         ` Kairui Song
2019-03-25  6:47         ` Junichi Nomura
2019-03-25  6:59           ` Dave Young [this message]
2019-03-25  8:27             ` [PATCH v2] " Junichi Nomura
2019-03-25  8:54               ` Boris Petkov
2019-03-25  9:25                 ` [PATCH v2] x86/boot: Don't try to search RSDP from EFI when kexec-booted Junichi Nomura
2019-03-25 10:15                 ` [PATCH v2] x86/boot: Use EFI setup data if provided Dave Young
2019-03-25 10:36                   ` Junichi Nomura
2019-03-25 11:16                     ` Dave Young
2019-03-25 12:01                     ` Borislav Petkov
2019-03-25 12:23                       ` Dave Young
2019-03-25 12:32                         ` Borislav Petkov
2019-03-25 23:10                           ` Junichi Nomura
2019-03-26 12:46                             ` Dave Young
2019-03-26 13:57                             ` Borislav Petkov
2019-03-27  1:48                               ` bhe
2019-03-27 12:14                                 ` Borislav Petkov
2019-03-28  4:17                                 ` Junichi Nomura
2019-03-28  6:26                                   ` Chao Fan
2019-03-28  6:43                                   ` bhe
2019-03-28  7:43                                     ` Junichi Nomura
2019-03-28 15:52                                       ` Borislav Petkov
2019-03-29  3:05                                         ` Junichi Nomura
2019-03-29  8:39                                           ` Borislav Petkov
2019-03-29  9:05                                             ` Chao Fan
2019-03-29  9:16                                               ` Borislav Petkov
2019-03-29  9:37                                                 ` Junichi Nomura
2019-03-29  9:44                                                   ` Chao Fan
2019-03-29  9:56                                                     ` Junichi Nomura
2019-03-29  7:20                                         ` [PATCH] x86/boot: Use efi_setup_data for searching RSDP on kexec-ed kernel Junichi Nomura
2019-03-29  7:49                                           ` bhe
2019-03-29  8:29                                           ` Chao Fan
2019-03-29  8:39                                             ` Junichi Nomura
2019-03-29  9:18                                               ` Chao Fan
2019-03-29  9:16                                             ` bhe
2019-03-29  9:20                                               ` Chao Fan
2019-04-01  0:08                                         ` [PATCH v2] " Junichi Nomura
2019-04-02  9:41                                           ` Chao Fan
2019-04-02  9:53                                             ` Junichi Nomura
2019-04-02 11:06                                               ` Chao Fan
2019-04-02 10:22                                                 ` Junichi Nomura
2019-04-02 12:03                                           ` Dave Young
2019-04-03  5:35                                             ` Chao Fan
2019-04-03  5:53                                               ` Dave Young
2019-04-03  6:39                                                 ` Dave Young
2019-04-03  7:30                                                   ` Chao Fan
2019-04-03  7:50                                                     ` bhe
2019-04-03  8:23                                                       ` Dave Young
2019-04-03  8:26                                                         ` Dave Young
2019-04-03 16:14                                                           ` Borislav Petkov
2019-04-04  1:02                                                             ` Chao Fan
2019-04-03  9:28                                                       ` Chao Fan
2019-04-03  7:21                                                 ` Chao Fan
2019-04-03  8:09                                                   ` Dave Young
2019-04-03  8:23                                                     ` Chao Fan
2019-04-03  9:02                                                       ` Chao Fan
2019-04-03  9:39                                                         ` Chao Fan
2019-04-04  1:23                                                         ` Junichi Nomura
2019-04-04  2:52                                                           ` Dave Young
2019-04-04  3:00                                                             ` bhe
2019-04-04  3:10                                                               ` bhe
2019-04-04  3:22                                                                 ` Dave Young
2019-04-04  6:41                                                                   ` Dave Young
2019-04-04  7:20                                                                     ` Chao Fan
2019-04-04  7:41                                                                       ` Dave Young
2019-04-04  7:48                                                                         ` Chao Fan
2019-04-04 12:22                                                                         ` Borislav Petkov
2019-04-04 14:08                                                                           ` Dave Young
2019-04-03  8:18                                                   ` Dave Young
2019-04-02 10:25                                         ` [PATCH v3] " Junichi Nomura
2019-04-04  7:32                                           ` Dave Young
2019-04-04 12:24                                             ` Borislav Petkov
2019-04-04 14:12                                               ` Dave Young
2019-04-04 14:41                                                 ` Borislav Petkov
2019-04-05  1:36                                                   ` Dave Young
2019-04-05  4:19                                             ` Junichi Nomura
2019-03-28 23:11                                       ` [PATCH v2] x86/boot: Use EFI setup data if provided bhe
2019-03-29  3:34                                         ` Junichi Nomura
2019-03-29  3:52                                           ` bhe
2019-03-29  5:16                                             ` Junichi Nomura
2019-03-25  7:27   ` [PATCH] " Baoquan He
2019-03-25  7:53     ` Borislav Petkov
2019-03-25  8:21       ` Baoquan He
2019-03-25  8:43         ` Thomas Gleixner
2019-03-25  9:03           ` Baoquan He

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