like below:
>>> while(TRUE) {
>>> if (error) {
>>> break;
>>> }
>>>GetData
>>>if (complete) {
>>> Break
>>>}
>>> }
>>>
>>> BME clear will trigger error break.
>>>
>>
@intel.com>; Laszlo Ersek <ler...@redhat.com>;
>> Zeng, Star <star.z...@intel.com>; edk2-devel@lists.01.org
>> Cc: Ard Biesheuvel <ard.biesheu...@linaro.org>; Kinney, Michael D
>> <michael.d.kin...@intel.com>
>> Subject: RE: [edk2] [PATCH] Intel
>; Laszlo Ersek <ler...@redhat.com>;
> Zeng, Star <star.z...@intel.com>; edk2-devel@lists.01.org
> Cc: Ard Biesheuvel <ard.biesheu...@linaro.org>; Kinney, Michael D
> <michael.d.kin...@intel.com>
> Subject: RE: [edk2] [PATCH] IntelSiliconPkg/VTdDxe: Change EBS
lists.01.org
> Cc: Ard Biesheuvel <ard.biesheu...@linaro.org>; Kinney, Michael D
> <michael.d.kin...@intel.com>
> Subject: RE: [edk2] [PATCH] IntelSiliconPkg/VTdDxe: Change EBS Event TPL to
> CALLBACK.
>
> I think the error might be PCI device specific.
>
> BT
D
> <michael.d.kin...@intel.com>
> Subject: RE: [edk2] [PATCH] IntelSiliconPkg/VTdDxe: Change EBS Event TPL to
> CALLBACK.
>
> Jiewen,
> If the BME bit is cleared in Command register, but a device driver
> uses DMA to transfer data, what kind of error will be seen by S
intel.com>;
edk2-devel@lists.01.org
Cc: Ni, Ruiyu <ruiyu...@intel.com>; Ard Biesheuvel <ard.biesheu...@linaro.org>;
Kinney, Michael D <michael.d.kin...@intel.com>
Subject: RE: [edk2] [PATCH] IntelSiliconPkg/VTdDxe: Change EBS Event TPL to
CALLBACK.
Good Info. I think a correct
.@intel.com>; Zeng, Star <star.z...@intel.com>;
> edk2-devel@lists.01.org
> Cc: Ni, Ruiyu <ruiyu...@intel.com>; Ard Biesheuvel
> <ard.biesheu...@linaro.org>;
> Kinney, Michael D <michael.d.kin...@intel.com>
> Subject: Re: [edk2] [PATCH] IntelSiliconPkg/VTdDxe
To: Zeng, Star <star.z...@intel.com>; Yao, Jiewen <jiewen@intel.com>;
>> edk2-devel@lists.01.org
>> Cc: Ni, Ruiyu <ruiyu...@intel.com>; Ard Biesheuvel
>> <ard.biesheu...@linaro.org>
>> Subject: Re: [edk2] [PATCH] IntelSiliconPkg/VTdDxe: Chan
gt; edk2-devel@lists.01.org
> Cc: Ni, Ruiyu <ruiyu...@intel.com>; Ard Biesheuvel <ard.biesheu...@linaro.org>
> Subject: Re: [edk2] [PATCH] IntelSiliconPkg/VTdDxe: Change EBS Event TPL to
> CALLBACK.
>
> On 10/26/17 10:10, Zeng, Star wrote:
> > Is it security reason
On 10/26/17 10:10, Zeng, Star wrote:
> Is it security reason when IOMMU disabled and Bus Master not disabled?
No, I don't think there is a security issue here.
But, my previous assessment about VTdDxe was indeed wrong -- there may
be a *correctness* issue.
Namely, if the IOMMU is de-activated
Is it security reason when IOMMU disabled and Bus Master not disabled?
Could our code have a central place to disable Bus Master? For example
PciBusDxe?
Thanks,
Star
-Original Message-
From: Laszlo Ersek [mailto:ler...@redhat.com]
Sent: Thursday, October 26, 2017 3:53 PM
To: Zeng,
On 10/26/17 08:54, Zeng, Star wrote:
> Ok, please add more description into the commit log, for example, "PCI device
> should disable BME at NOTIFY", etc.
Last time we discussed this question, the consensus was that edk2 should
not present any requirement for PCI drivers that is not required by
Agree!
> -Original Message-
> From: Zeng, Star
> Sent: Thursday, October 26, 2017 2:55 PM
> To: Yao, Jiewen ; edk2-devel@lists.01.org
> Cc: Laszlo Ersek (ler...@redhat.com) ; Ni, Ruiyu
> ; Zeng, Star
>
Ok, please add more description into the commit log, for example, "PCI device
should disable BME at NOTIFY", etc.
With that, Reviewed-by: Star Zeng
Thanks,
Star
-Original Message-
From: Yao, Jiewen
Sent: Thursday, October 26, 2017 2:51 PM
To: Zeng, Star
Yes, this PCI patch will be submitted soon. :)
Thank you
Yao Jiewen
> -Original Message-
> From: Zeng, Star
> Sent: Thursday, October 26, 2017 2:18 PM
> To: Yao, Jiewen ; edk2-devel@lists.01.org
> Cc: Laszlo Ersek (ler...@redhat.com) ; Zeng, Star
So there will be a guidance for this " PCI device disable BME at NOTIFY " to be
documented?
Thanks,
Star
-Original Message-
From: Yao, Jiewen
Sent: Thursday, October 26, 2017 2:03 PM
To: Zeng, Star ; edk2-devel@lists.01.org
Cc: Laszlo Ersek (ler...@redhat.com)
Right. In the future, we will let PCI device disable BME at NOTIFY.
So we let IOMMU use CALLBACK, to make sure BME is disabled before IOMMU is
disabled.
Thank you
Yao Jiewen
> -Original Message-
> From: Zeng, Star
> Sent: Thursday, October 26, 2017 1:55 PM
> To: Yao, Jiewen
I am confused.
Is this patch to make the device driver's EBS event notification to be run
before IntelVTdDxe's EBS event notification?
If yes, this patch seemingly can only make sure the behavior when the device
driver's EBS event notification is at NOTIFY, but not CALLBACK.
Thanks,
Star
That is fine.
Here, disabling IOMMU means to disable the protection and allow all DMA access.
I do not think it will bring any functional impact.
Thank you
Yao Jiewen
> -Original Message-
> From: Zeng, Star
> Sent: Thursday, October 26, 2017 12:58 PM
> To: Yao, Jiewen
Some device driver may also have exit boot service event at CALLBACK, for
example AtaPassThruExitBootServices() that was added by Laszlo.
Thanks,
Star
-Original Message-
From: Yao, Jiewen
Sent: Thursday, October 26, 2017 10:14 AM
To: edk2-devel@lists.01.org
Cc: Zeng, Star
Change ExitBootServices TPL to CALLBACK, so that a device
can disable BME before IOMMU grants access right.
Cc: Star Zeng
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Jiewen Yao
---
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