From: Junichi Nomura <j-nomura@ce.jp.nec.com>
To: Borislav Petkov <bp@alien8.de>
Cc: Dave Young <dyoung@redhat.com>,
Chao Fan <fanc.fnst@cn.fujitsu.com>, Baoquan He <bhe@redhat.com>,
Kairui Song <kasong@redhat.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>
Subject: Re: [PATCH v4] x86/boot: Use efi_setup_data for searching RSDP on kexec-ed kernel
Date: Thu, 11 Apr 2019 08:16:45 +0000 [thread overview]
Message-ID: <e4de0520-ade8-2834-dadf-7af68701356b@ce.jp.nec.com> (raw)
In-Reply-To: <20190411080927.GA30080@zn.tnic>
On 4/11/19 5:09 PM, Borislav Petkov wrote:
> On Wed, Apr 10, 2019 at 11:34:51PM +0000, Junichi Nomura wrote:
>> But efi_get_rsdp_addr() needs to check whether the kernel was
>> kexec booted to avoid accessing invalid EFI table address.
>> efi_get_kexec_setup_data_addr() is the only method I know
>> to check if it was kexec-booted.
>
> Your v3 had the right approach - you first check if you can get the
> address as a kexec-ed kernel. If you do, you use that one and continue
> the normal path.
>
> If you don't, you fall back to efi_get_rsdp_addr() and get it directly
> from EFI.
>
> And then carve out the functionality you need to call multiple times in
> helper functions like __efi_get_rsdp_addr().
>
> Why doesn't that work anymore?
kexec_get_rsdp_addr() might fail on kexec-booted kernel, e.g. if the
setup_data was invalid. In such a case, falling back to efi_get_rsdp_addr()
will hit the problem of accessing invalid table pointer again.
--
Jun'ichi Nomura, NEC Corporation / NEC Solution Innovators, Ltd.
WARNING: multiple messages have this Message-ID (diff)
From: Junichi Nomura <j-nomura@ce.jp.nec.com>
To: Borislav Petkov <bp@alien8.de>
Cc: Chao Fan <fanc.fnst@cn.fujitsu.com>,
Kairui Song <kasong@redhat.com>, Baoquan He <bhe@redhat.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>,
Dave Young <dyoung@redhat.com>
Subject: Re: [PATCH v4] x86/boot: Use efi_setup_data for searching RSDP on kexec-ed kernel
Date: Thu, 11 Apr 2019 08:16:45 +0000 [thread overview]
Message-ID: <e4de0520-ade8-2834-dadf-7af68701356b@ce.jp.nec.com> (raw)
In-Reply-To: <20190411080927.GA30080@zn.tnic>
On 4/11/19 5:09 PM, Borislav Petkov wrote:
> On Wed, Apr 10, 2019 at 11:34:51PM +0000, Junichi Nomura wrote:
>> But efi_get_rsdp_addr() needs to check whether the kernel was
>> kexec booted to avoid accessing invalid EFI table address.
>> efi_get_kexec_setup_data_addr() is the only method I know
>> to check if it was kexec-booted.
>
> Your v3 had the right approach - you first check if you can get the
> address as a kexec-ed kernel. If you do, you use that one and continue
> the normal path.
>
> If you don't, you fall back to efi_get_rsdp_addr() and get it directly
> from EFI.
>
> And then carve out the functionality you need to call multiple times in
> helper functions like __efi_get_rsdp_addr().
>
> Why doesn't that work anymore?
kexec_get_rsdp_addr() might fail on kexec-booted kernel, e.g. if the
setup_data was invalid. In such a case, falling back to efi_get_rsdp_addr()
will hit the problem of accessing invalid table pointer again.
--
Jun'ichi Nomura, NEC Corporation / NEC Solution Innovators, Ltd.
_______________________________________________
kexec mailing list
kexec@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kexec
next prev parent reply other threads:[~2019-04-11 8:18 UTC|newest]
Thread overview: 95+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-04-08 23:10 [PATCH v4] x86/boot: Use efi_setup_data for searching RSDP on kexec-ed kernel Junichi Nomura
2019-04-08 23:10 ` Junichi Nomura
2019-04-10 17:14 ` Borislav Petkov
2019-04-10 17:14 ` Borislav Petkov
2019-04-10 23:34 ` Junichi Nomura
2019-04-10 23:34 ` Junichi Nomura
2019-04-11 8:09 ` Borislav Petkov
2019-04-11 8:09 ` Borislav Petkov
2019-04-11 8:16 ` Junichi Nomura [this message]
2019-04-11 8:16 ` Junichi Nomura
2019-04-11 8:37 ` Borislav Petkov
2019-04-11 8:37 ` Borislav Petkov
2019-04-11 9:13 ` Junichi Nomura
2019-04-11 9:13 ` Junichi Nomura
2019-04-11 9:21 ` Boris Petkov
2019-04-11 9:21 ` Boris Petkov
2019-04-11 9:32 ` Junichi Nomura
2019-04-11 9:32 ` Junichi Nomura
2019-04-11 9:40 ` Boris Petkov
2019-04-11 9:40 ` Boris Petkov
2019-04-11 12:58 ` Borislav Petkov
2019-04-11 12:58 ` Borislav Petkov
2019-04-12 2:54 ` Junichi Nomura
2019-04-12 2:54 ` Junichi Nomura
2019-04-12 8:49 ` Borislav Petkov
2019-04-12 8:49 ` Borislav Petkov
2019-04-12 13:35 ` Borislav Petkov
2019-04-12 13:35 ` Borislav Petkov
2019-04-15 7:01 ` Junichi Nomura
2019-04-15 7:01 ` Junichi Nomura
2019-04-15 9:07 ` Borislav Petkov
2019-04-15 9:07 ` Borislav Petkov
2019-04-15 10:25 ` Borislav Petkov
2019-04-15 10:25 ` Borislav Petkov
2019-04-15 23:00 ` Junichi Nomura
2019-04-15 23:00 ` Junichi Nomura
2019-04-15 23:14 ` Junichi Nomura
2019-04-15 23:14 ` Junichi Nomura
2019-04-16 9:45 ` Borislav Petkov
2019-04-16 9:45 ` Borislav Petkov
2019-04-16 23:09 ` kexec crash on OVMF i386 + x86_64 kernel (Re: [PATCH v4] x86/boot: Use efi_setup_data for searching RSDP on kexec-ed kernel) Junichi Nomura
2019-04-16 23:09 ` Junichi Nomura
2019-04-17 5:14 ` Dave Young
2019-04-17 5:14 ` Dave Young
2019-04-17 17:57 ` Prakhya, Sai Praneeth
2019-04-17 17:57 ` Prakhya, Sai Praneeth
2019-04-16 9:40 ` [PATCH v4] x86/boot: Use efi_setup_data for searching RSDP on kexec-ed kernel Borislav Petkov
2019-04-16 9:40 ` Borislav Petkov
2019-04-16 9:52 ` [PATCH] x86/boot: Use efi_setup_data for searching RSDP on kexec-ed kernels Borislav Petkov
2019-04-16 9:52 ` Borislav Petkov
2019-04-16 10:02 ` Ingo Molnar
2019-04-16 10:02 ` Ingo Molnar
2019-04-16 10:31 ` Borislav Petkov
2019-04-16 10:31 ` Borislav Petkov
2019-04-16 11:41 ` Dave Young
2019-04-16 11:41 ` Dave Young
2019-04-16 13:22 ` Borislav Petkov
2019-04-16 13:22 ` Borislav Petkov
2019-04-17 1:38 ` Dave Young
2019-04-17 1:38 ` Dave Young
2019-04-17 4:57 ` Dave Young
2019-04-17 4:57 ` Dave Young
2019-04-17 6:00 ` Kairui Song
2019-04-17 6:00 ` Kairui Song
2019-04-17 7:08 ` Dave Young
2019-04-17 7:08 ` Dave Young
2019-04-17 8:22 ` Borislav Petkov
2019-04-17 8:22 ` Borislav Petkov
2019-04-18 1:24 ` Dave Young
2019-04-18 1:24 ` Dave Young
2019-04-19 8:34 ` [RFC PATCH] kexec, x86/boot: map systab region in identity mapping before accessing it Kairui Song
2019-04-19 8:34 ` Kairui Song
2019-04-19 8:58 ` Baoquan He
2019-04-19 8:58 ` Baoquan He
2019-04-19 9:39 ` Kairui Song
2019-04-19 9:39 ` Kairui Song
2019-04-16 22:44 ` [PATCH v4] x86/boot: Use efi_setup_data for searching RSDP on kexec-ed kernel Junichi Nomura
2019-04-16 22:44 ` Junichi Nomura
2019-04-17 7:02 ` Dave Young
2019-04-17 7:02 ` Dave Young
2019-04-17 8:54 ` Borislav Petkov
2019-04-17 8:54 ` Borislav Petkov
2019-04-17 9:02 ` Borislav Petkov
2019-04-17 9:02 ` Borislav Petkov
2019-04-17 10:31 ` Chao Fan
2019-04-17 10:31 ` Chao Fan
2019-04-11 8:42 ` Baoquan He
2019-04-11 8:42 ` Baoquan He
2019-04-11 9:14 ` Junichi Nomura
2019-04-11 9:14 ` Junichi Nomura
2019-04-12 0:23 ` Baoquan He
2019-04-12 0:23 ` Baoquan He
2019-04-15 7:46 ` Dave Young
2019-04-15 7:46 ` Dave Young
2019-06-06 19:22 ` [tip:x86/boot] x86/boot: Use efi_setup_data for searching RSDP on kexec-ed kernels tip-bot for Junichi Nomura
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