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From: Christoph Hellwig <hch@infradead.org>
To: Konrad Rzeszutek Wilk <konrad@darnok.org>
Cc: Christoph Hellwig <hch@infradead.org>,
	Maurizio Lombardi <mlombard@redhat.com>,
	rppt@kernel.org, bp@alien8.de, tglx@linutronix.de,
	x86@kernel.org, pjones@redhat.com, konrad@kernel.org,
	george.kennedy@oracle.com, rafael@kernel.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH V3] iscsi_ibft: fix crash due to KASLR physical memory remapping
Date: Wed, 11 Aug 2021 07:57:25 +0100	[thread overview]
Message-ID: <YRN01YySPVucdCF0@infradead.org> (raw)
In-Reply-To: <YRK9fxhyPgEzWKce@localhost.localdomain>

On Tue, Aug 10, 2021 at 01:55:11PM -0400, Konrad Rzeszutek Wilk wrote:
> On Tue, Aug 10, 2021 at 06:00:24PM +0100, Christoph Hellwig wrote:
> > > Fix this bug by saving the address of the physical location
> > > of the ibft; later the driver will use isa_bus_to_virt() to get
> > > the correct virtual address.
> > 
> > That sound rather broken.  Why not save the physical address in
> > find_ibft_region and then later ioremap that when a virtual address is
> > needed like all other code accessing magic I/O memory?
> 
> That is kind of what he does. The physical address is saved as a global
> static variable and also the physical address is memreserved. Then
> later on the physical address is used to create the virtual address.

Except that it uses isa_bus_to_virt, which is really broken.

> Or are you thinking of making the find_ibft_region reserve the physical
> address, and _cache_ the physical address so there is no global
> variable ?

No.  Just switch to ioremap/early_ioremap insted of this isa_bus_to_virt
mess.

  reply	other threads:[~2021-08-11  6:59 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-29 13:52 Maurizio Lombardi
2021-07-29 17:03 ` Konrad Rzeszutek Wilk
2021-07-29 19:20   ` Maurizio Lombardi
2021-07-29 19:31 ` Mike Rapoport
2021-08-01  2:44   ` Konrad Rzeszutek Wilk
2021-08-10 17:00 ` Christoph Hellwig
2021-08-10 17:55   ` Konrad Rzeszutek Wilk
2021-08-11  6:57     ` Christoph Hellwig [this message]
2021-08-11  7:20       ` Mike Rapoport
2021-09-01 16:47 ` Guenter Roeck

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