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Subject: Re: [PATCH] cxl: fix setting of _PAGE_USER bit when handling page
 faults
From: "Matthew R. Ochs" <mrochs@linux.vnet.ibm.com>
In-Reply-To: <1458273681-18588-1-git-send-email-andrew.donnellan@au1.ibm.com>
Date: Tue, 29 Mar 2016 17:08:10 -0500
Cc: linuxppc-dev@lists.ozlabs.org, imunsie@au1.ibm.com
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References: <1458273681-18588-1-git-send-email-andrew.donnellan@au1.ibm.com>
To: Andrew Donnellan <andrew.donnellan@au1.ibm.com>
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> On Mar 17, 2016, at 11:01 PM, Andrew Donnellan =
<andrew.donnellan@au1.ibm.com> wrote:
>=20
> When handling page faults, cxl_handle_page_fault() checks whether the =
page
> should be accessible by userspace and have its _PAGE_USER access bit =
set.
> _PAGE_USER should be set if the context's kernel flag isn't set, or if =
the
> page falls outside of kernel memory.
>=20
> However, the check currently uses the wrong operator, causing it to =
always
> evalute to true. As such, we always set the _PAGE_USER bit, even when =
it
> should be restricted to the kernel.
>=20
> Fix the check so that the _PAGE_USER bit is set only as intended.
>=20
> Fixes: f204e0b8cedd ("cxl: Driver code for powernv PCIe based cards =
for
> userspace access")
> Signed-off-by: Andrew Donnellan <andrew.donnellan@au1.ibm.com>

Per Ian's suggestion, I went ahead and tried this with cxlflash.

Tested-by: Matthew R. Ochs <mrochs@linux.vnet.ibm.com>