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From: Paolo Bonzini <pbonzini@redhat.com>
To: Igor Mammedov <imammedo@redhat.com>
Cc: "Yao, Jiewen" <jiewen.yao@intel.com>,
	Laszlo Ersek <lersek@redhat.com>,
	edk2-devel-groups-io <devel@edk2.groups.io>,
	edk2-rfc-groups-io <rfc@edk2.groups.io>,
	qemu devel list <qemu-devel@nongnu.org>,
	"Chen, Yingwen" <yingwen.chen@intel.com>,
	"Nakajima, Jun" <jun.nakajima@intel.com>,
	Boris Ostrovsky <boris.ostrovsky@oracle.com>,
	Joao Marcal Lemos Martins <joao.m.martins@oracle.com>,
	Phillip Goerl <phillip.goerl@oracle.com>
Subject: Re: CPU hotplug using SMM with QEMU+OVMF
Date: Thu, 15 Aug 2019 18:24:53 +0200	[thread overview]
Message-ID: <f6c58790-7298-d991-844e-48f4a9dc8937@redhat.com> (raw)
In-Reply-To: <20190815180733.4b396b5d@redhat.com>

On 15/08/19 18:07, Igor Mammedov wrote:
> Looking at Q35 code and Seabios SMM relocation as example, if I see it
> right QEMU has:
>     - SMRAM is aliased from DRAM at 0xa0000
>     - and TSEG steals from the top of low RAM when configured
> 
> Now problem is that default SMBASE at 0x30000 isn't backed by anything
> in SMRAM address space and default SMI entry falls-through to the same
> location in System address space.
> 
> The later is not trusted and entry into SMM mode will corrupt area + might
> jump to 'random' SMI handler (hence save/restore code in Seabios).
> 
> Here is an idea, can we map a memory region at 0x30000 in SMRAM address
> space with relocation space/code reserved. It could be a part of TSEG
> (so we don't have to invent ABI to configure that)?

No, there could be real mode code using it.  What we _could_ do is
initialize SMBASE to 0xa0000, but I think it's better to not deviate too
much from processor behavior (even if it's admittedly a 20-years legacy
that doesn't make any sense).

Paolo

  reply	other threads:[~2019-08-15 16:24 UTC|newest]

Thread overview: 69+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-08-13 14:16 CPU hotplug using SMM with QEMU+OVMF Laszlo Ersek
2019-08-13 16:09 ` Laszlo Ersek
2019-08-13 16:18   ` Laszlo Ersek
2019-08-14 13:20   ` Yao, Jiewen
2019-08-14 14:04     ` Paolo Bonzini
2019-08-15  9:55       ` Yao, Jiewen
2019-08-15 16:04         ` Paolo Bonzini
2019-08-15 15:00       ` [edk2-devel] " Laszlo Ersek
2019-08-15 16:16         ` Igor Mammedov
2019-08-15 16:21         ` Paolo Bonzini
2019-08-16  2:46           ` Yao, Jiewen
2019-08-16  7:20             ` Paolo Bonzini
2019-08-16  7:49               ` Yao, Jiewen
2019-08-16 20:15                 ` Laszlo Ersek
2019-08-16 22:19                   ` Alex Williamson
2019-08-17  0:20                     ` Yao, Jiewen
2019-08-18 19:50                       ` Paolo Bonzini
2019-08-18 23:00                         ` Yao, Jiewen
2019-08-19 14:10                           ` Paolo Bonzini
2019-08-21 12:07                             ` Laszlo Ersek
2019-08-21 15:48                           ` [edk2-rfc] " Michael D Kinney
2019-08-21 17:05                             ` Paolo Bonzini
2019-08-21 17:25                               ` Michael D Kinney
2019-08-21 17:39                                 ` Paolo Bonzini
2019-08-21 20:17                                   ` Michael D Kinney
2019-08-22  6:18                                     ` Paolo Bonzini
2019-08-22 18:29                                       ` Laszlo Ersek
2019-08-22 18:51                                         ` Paolo Bonzini
2019-08-23 14:53                                           ` Laszlo Ersek
2019-08-22 20:13                                         ` Michael D Kinney
2019-08-22 17:59                               ` Laszlo Ersek
2019-08-22 18:43                                 ` Paolo Bonzini
2019-08-22 20:06                                   ` Michael D Kinney
2019-08-22 22:18                                     ` Paolo Bonzini
2019-08-22 22:32                                       ` Michael D Kinney
2019-08-22 23:11                                         ` Paolo Bonzini
2019-08-23  1:02                                           ` Michael D Kinney
2019-08-23  5:00                                             ` Yao, Jiewen
2019-08-23 15:25                                               ` Michael D Kinney
2019-08-24  1:48                                                 ` Yao, Jiewen
2019-08-27 18:31                                                   ` Igor Mammedov
2019-08-29 17:01                                                     ` Laszlo Ersek
2019-08-30 14:48                                                       ` Igor Mammedov
2019-08-30 18:46                                                         ` Laszlo Ersek
2019-09-02  8:45                                                           ` Igor Mammedov
2019-09-02 19:09                                                             ` Laszlo Ersek
2019-09-03 14:53                                                               ` [Qemu-devel] " Igor Mammedov
2019-09-03 17:20                                                                 ` Laszlo Ersek
2019-09-04  9:52                                                                   ` imammedo
2019-09-05 13:08                                                                     ` Laszlo Ersek
2019-09-05 15:45                                                                       ` Igor Mammedov
2019-09-05 15:49                                                                       ` [PATCH] q35: lpc: allow to lock down 128K RAM at default SMBASE address Igor Mammedov
2019-09-09 19:15                                                                         ` Laszlo Ersek
2019-09-09 19:20                                                                           ` Laszlo Ersek
2019-09-10 15:58                                                                           ` Igor Mammedov
2019-09-11 17:30                                                                             ` Laszlo Ersek
2019-09-17 13:11                                                                               ` [edk2-devel] " Igor Mammedov
2019-09-17 14:38                                                                                 ` [staging/branch]: CdePkg - C Development Environment Package Minnow Ware
2019-08-26 15:30                                                 ` [edk2-rfc] [edk2-devel] CPU hotplug using SMM with QEMU+OVMF Laszlo Ersek
2019-08-27 16:23                                                   ` Igor Mammedov
2019-08-27 20:11                                                     ` Laszlo Ersek
2019-08-28 12:01                                                       ` Igor Mammedov
2019-08-29 16:25                                                         ` Laszlo Ersek
2019-08-30 13:49                                                           ` [Qemu-devel] " Igor Mammedov
2019-08-22 17:53                             ` Laszlo Ersek
2019-08-16 20:00           ` Laszlo Ersek
2019-08-15 16:07       ` Igor Mammedov
2019-08-15 16:24         ` Paolo Bonzini [this message]
2019-08-16  7:42           ` Igor Mammedov

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