From: Joerg Roedel <joro@8bytes.org>
To: Lu Baolu <baolu.lu@linux.intel.com>
Cc: Kevin Tian <kevin.tian@intel.com>,
Ashok Raj <ashok.raj@intel.com>,
linux-kernel@vger.kernel.org,
Andy Lutomirski <luto@amacapital.net>,
iommu@lists.linux-foundation.org
Subject: Re: [PATCH v3 1/1] iommu/vt-d: Serialize IOMMU GCMD register modifications
Date: Fri, 4 Sep 2020 11:39:45 +0200 [thread overview]
Message-ID: <20200904093945.GO6714@8bytes.org> (raw)
In-Reply-To: <20200828000615.8281-1-baolu.lu@linux.intel.com>
On Fri, Aug 28, 2020 at 08:06:15AM +0800, Lu Baolu wrote:
> The VT-d spec requires (10.4.4 Global Command Register, GCMD_REG General
> Description) that:
>
> If multiple control fields in this register need to be modified, software
> must serialize the modifications through multiple writes to this register.
>
> However, in irq_remapping.c, modifications of IRE and CFI are done in one
> write. We need to do two separate writes with STS checking after each. It
> also checks the status register before writing command register to avoid
> unnecessary register write.
>
> Fixes: af8d102f999a4 ("x86/intel/irq_remapping: Clean up x2apic opt-out security warning mess")
> Cc: Andy Lutomirski <luto@amacapital.net>
> Cc: Jacob Pan <jacob.jun.pan@linux.intel.com>
> Cc: Kevin Tian <kevin.tian@intel.com>
> Cc: Ashok Raj <ashok.raj@intel.com>
> Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
> ---
> drivers/iommu/intel/irq_remapping.c | 10 ++++++++--
> 1 file changed, 8 insertions(+), 2 deletions(-)
Applied for v5.9, thanks.
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prev parent reply other threads:[~2020-09-04 9:39 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-28 0:06 [PATCH v3 1/1] iommu/vt-d: Serialize IOMMU GCMD register modifications Lu Baolu
2020-08-28 1:32 ` Tian, Kevin
2020-09-04 9:39 ` Joerg Roedel [this message]
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