Regression with xhci console (was: [PATCH 1/4] amd-vi: fix IVMD memory type checks) - Marek Marczykowski-Górecki

From: "Marek Marczykowski-Górecki" <marmarek@invisiblethingslab.com>
To: Roger Pau Monne <roger.pau@citrix.com>
Cc: xen-devel@lists.xenproject.org, Jan Beulich <jbeulich@suse.com>,
	Andrew Cooper <andrew.cooper3@citrix.com>,
	oxjo@proton.me
Subject: Regression with xhci console (was: [PATCH 1/4] amd-vi: fix IVMD memory type checks)
Date: Mon, 11 Mar 2024 03:18:58 +0100	[thread overview]
Message-ID: <Ze5qE9yBLG0chLm2@mail-itl> (raw)
In-Reply-To: <20240201170159.66330-2-roger.pau@citrix.com>

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On Thu, Feb 01, 2024 at 06:01:56PM +0100, Roger Pau Monne wrote:
> The current code that parses the IVMD blocks is relaxed with regard to the
> restriction that such unity regions should always fall into memory ranges
> marked as reserved in the memory map.
> 
> However the type checks for the IVMD addresses are inverted, and as a result
> IVMD ranges falling into RAM areas are accepted.  Note that having such ranges
> in the first place is a firmware bug, as IVMD should always fall into reserved
> ranges.
> 
> Fixes: ed6c77ebf0c1 ('AMD/IOMMU: check / convert IVMD ranges for being / to be reserved')
> Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>

FYI Xen 4.17.3 with this patch (but not others in the series) causes
panic on boot on Framework 14 AMD laptop:

    (XEN)  [0000000044570000, 000000005077efff] (usable)
    ...
    (XEN) AMD-Vi: Warning: IVMD: [4f83f000,4f880000) is not (entirely) in reserved memory
    (XEN) AMD-Vi: Error: IVMD: page at 4f83f000 can't be converted
    ...
    (XEN) Xen BUG at drivers/passthrough/amd/iommu_init.c:1386

Full boot log at https://github.com/QubesOS/qubes-issues/issues/9030
4.17.2 worked fine.
I'll try the whole series (and the follow up one), but I don't expect
any difference.

This looks to be related to XHCI console, which does use the same API to
allow device to DMA into relevant buffers even when the rest of XHCI is
used by dom0 (or even other domain if 'share=yes' is used):
https://gitlab.com/xen-project/xen/-/blob/staging/xen/drivers/char/xhci-dbc.c?ref_type=heads#L1421-1424

-- 
Best Regards,
Marek Marczykowski-Górecki
Invisible Things Lab

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