linux-kernel - Re: [RFC PATCH v8 5/5] iommu/vt-d: don't loop for timeout device-TLB invalidation request forever

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: <c659a328-ff5f-4750-9cbe-b18fc9ffe7e6@linux.intel.com>
Date: Wed, 27 Dec 2023 11:11:06 +0800
From: Ethan Zhao <haifeng.zhao@...ux.intel.com>
To: bhelgaas@...gle.com, baolu.lu@...ux.intel.com, dwmw2@...radead.org,
 will@...nel.org, robin.murphy@....com, lukas@...ner.de
Cc: linux-pci@...r.kernel.org, iommu@...ts.linux.dev,
 linux-kernel@...r.kernel.org
Subject: Re: [RFC PATCH v8 5/5] iommu/vt-d: don't loop for timeout device-TLB
 invalidation request forever


On 12/27/2023 10:59 AM, Ethan Zhao wrote:
> When the device-TLB invalidation (ATS invalidation) timeout happens, the
> qi_submit_sync() will restart and loop for the invalidation request
> forever till it is done, it will block another invalidation thread such
> as the fq_timer to issue invalidation request, cause the system lockup as
> following
>
> [exception RIP: native_queued_spin_lock_slowpath+92]
>
> RIP: ffffffffa9d1025c RSP: ffffb202f268cdc8 RFLAGS: 00000002
>
> RAX: 0000000000000101 RBX: ffffffffab36c2a0 RCX: 0000000000000000
>
> RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffffab36c2a0
>
> RBP: ffffffffab36c2a0 R8: 0000000000000001 R9: 0000000000000000
>
> R10: 0000000000000010 R11: 0000000000000018 R12: 0000000000000000
>
> R13: 0000000000000004 R14: ffff9e10d71b1c88 R15: ffff9e10d71b1980
>
> ORIG_RAX: ffffffffffffffff CS: 0010 SS: 0018

Wrong past, please ignore this series.


Thanks,

Ethan


>
> --- ---
>
> (the left part of exception see the hotplug case of ATS capable device)
>
> If one endpoint device just no response to the device-TLB invalidation
> request, but is not gone, it will bring down the whole system, to avoid
> such case, don't try the timeout device-TLB request forever.
>
> and as synchronous program model of current qi_submit_sync() implementation
> we couldn't wait for the enough time as PCIe spec said 1min+50%, just break
> it in current sync model. (PCIe spec r6.1, sec 10.3.1)
>
> Signed-off-by: Ethan Zhao <haifeng.zhao@...ux.intel.com>
> ---
>   drivers/iommu/intel/dmar.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/iommu/intel/dmar.c b/drivers/iommu/intel/dmar.c
> index 76903a8bf963..206ab0b7294f 100644
> --- a/drivers/iommu/intel/dmar.c
> +++ b/drivers/iommu/intel/dmar.c
> @@ -1457,7 +1457,7 @@ int qi_submit_sync(struct intel_iommu *iommu, struct qi_desc *desc,
>   	reclaim_free_desc(qi);
>   	raw_spin_unlock_irqrestore(&qi->q_lock, flags);
>   
> -	if (rc == -EAGAIN)
> +	if (rc == -EAGAIN && type !=QI_DIOTLB_TYPE && type != QI_DEIOTLB_TYPE)
>   		goto restart;
>   
>   	if (iotlb_start_ktime)