linux-kernel - Re: [PATCH v2] soc: qcom: cmd-db: Map shared memory as WC, not WB

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <93c41b18-2280-496b-8328-9f46a68a6220@quicinc.com>
Date: Wed, 24 Jul 2024 10:31:51 +0530
From: Pavan Kondeti <quic_pkondeti@...cinc.com>
To: Caleb Connolly <caleb.connolly@...aro.org>,
        Bjorn Andersson
	<andersson@...nel.org>
CC: Maulik Shah <quic_mkshah@...cinc.com>,
        Bjorn Andersson
	<andersson@...nel.org>,
        Konrad Dybcio <konrad.dybcio@...aro.org>, <stephan@...hold.net>,
        <swboyd@...omium.org>, <dianders@...omium.org>, <robdclark@...il.com>,
        <nikita@...n.ru>, <quic_eberman@...cinc.com>,
        <quic_pkondeti@...cinc.com>, <quic_lsrao@...cinc.com>,
        <linux-arm-msm@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        "Volodymyr
 Babchuk" <Volodymyr_Babchuk@...m.com>,
        <stable@...r.kernel.org>
Subject: Re: [PATCH v2] soc: qcom: cmd-db: Map shared memory as WC, not WB

Hi Bjorn,

On Thu, Jul 18, 2024 at 09:41:34AM +0200, Caleb Connolly wrote:
> 
> 
> On 18/07/2024 08:03, Maulik Shah wrote:
> > From: Volodymyr Babchuk <Volodymyr_Babchuk@...m.com>
> > 
> > Linux does not write into cmd-db region. This region of memory is write
> > protected by XPU. XPU may sometime falsely detect clean cache eviction
> > as "write" into the write protected region leading to secure interrupt
> > which causes an endless loop somewhere in Trust Zone.
> > 
> > The only reason it is working right now is because Qualcomm Hypervisor
> > maps the same region as Non-Cacheable memory in Stage 2 translation
> > tables. The issue manifests if we want to use another hypervisor (like
> > Xen or KVM), which does not know anything about those specific mappings.
> > 
> > Changing the mapping of cmd-db memory from MEMREMAP_WB to MEMREMAP_WT/WC
> > removes dependency on correct mappings in Stage 2 tables. This patch
> > fixes the issue by updating the mapping to MEMREMAP_WC.
> > 
> > I tested this on SA8155P with Xen.
> > 
> > Fixes: 312416d9171a ("drivers: qcom: add command DB driver")
> > Cc: stable@...r.kernel.org # 5.4+
> > Signed-off-by: Volodymyr Babchuk <volodymyr_babchuk@...m.com>
> > Tested-by: Nikita Travkin <nikita@...n.ru> # sc7180 WoA in EL2
> > Signed-off-by: Maulik Shah <quic_mkshah@...cinc.com>
> 
> Reviewed-by: Caleb Connolly <caleb.connolly@...aro.org>

Is it possible to include it in v6.11-rc?

Thanks,
Pavan