Re: [RFC] xen/arm: introduce XENFEAT_ARM_dom0_iommu

2021-02-23 Thread Stefano Stabellini
On Fri, 19 Feb 2021, Julien Grall wrote: > On 19/02/2021 01:42, Stefano Stabellini wrote: > > On Thu, 18 Feb 2021, Julien Grall wrote: > > > On 17/02/2021 23:54, Stefano Stabellini wrote: > > > > On Wed, 17 Feb 2021, Julien Grall wrote: > > > > > On 17/02/2021 02:00, Stefano Stabellini wrote: > > >

Re: [RFC] xen/arm: introduce XENFEAT_ARM_dom0_iommu

2021-02-19 Thread Julien Grall
Hi Stefano, On 19/02/2021 01:42, Stefano Stabellini wrote: On Thu, 18 Feb 2021, Julien Grall wrote: On 17/02/2021 23:54, Stefano Stabellini wrote: On Wed, 17 Feb 2021, Julien Grall wrote: On 17/02/2021 02:00, Stefano Stabellini wrote: But actually it was always wrong for Linux to enable swio

Re: [RFC] xen/arm: introduce XENFEAT_ARM_dom0_iommu

2021-02-18 Thread Stefano Stabellini
On Thu, 18 Feb 2021, Julien Grall wrote: > On 17/02/2021 23:54, Stefano Stabellini wrote: > > On Wed, 17 Feb 2021, Julien Grall wrote: > > > On 17/02/2021 02:00, Stefano Stabellini wrote: > > > > Hi all, > > > > > > > > Today Linux uses the swiotlb-xen driver (drivers/xen/swiotlb-xen.c) to > > > >

Re: [RFC] xen/arm: introduce XENFEAT_ARM_dom0_iommu

2021-02-18 Thread Julien Grall
Hi Stefano, On 17/02/2021 23:54, Stefano Stabellini wrote: On Wed, 17 Feb 2021, Julien Grall wrote: On 17/02/2021 02:00, Stefano Stabellini wrote: I saw that the topic has generated quite a bit of discussion. I suggest we keep gathering data and do brainstorming on the thread for a few days a

Re: [RFC] xen/arm: introduce XENFEAT_ARM_dom0_iommu

2021-02-18 Thread Julien Grall
Hi Stefano, On 17/02/2021 23:54, Stefano Stabellini wrote: On Wed, 17 Feb 2021, Julien Grall wrote: On 17/02/2021 02:00, Stefano Stabellini wrote: Hi all, Today Linux uses the swiotlb-xen driver (drivers/xen/swiotlb-xen.c) to translate addresses for DMA operations in Dom0. Specifically, swiot

Re: [RFC] xen/arm: introduce XENFEAT_ARM_dom0_iommu

2021-02-17 Thread Stefano Stabellini
On Wed, 17 Feb 2021, Julien Grall wrote: > On 17/02/2021 02:00, Stefano Stabellini wrote: > > Hi all, > > > > Today Linux uses the swiotlb-xen driver (drivers/xen/swiotlb-xen.c) to > > translate addresses for DMA operations in Dom0. Specifically, > > swiotlb-xen is used to translate the address of

Re: [RFC] xen/arm: introduce XENFEAT_ARM_dom0_iommu

2021-02-17 Thread Jan Beulich
On 17.02.2021 16:34, Bertrand Marquis wrote: >> On 17 Feb 2021, at 02:00, Stefano Stabellini wrote: >> Today Linux uses the swiotlb-xen driver (drivers/xen/swiotlb-xen.c) to >> translate addresses for DMA operations in Dom0. Specifically, >> swiotlb-xen is used to translate the address of a foreig

Re: [RFC] xen/arm: introduce XENFEAT_ARM_dom0_iommu

2021-02-17 Thread Julien Grall
On 17/02/2021 16:47, Bertrand Marquis wrote: Hi Julien, On 17 Feb 2021, at 16:41, Julien Grall wrote: On 17/02/2021 15:37, Bertrand Marquis wrote: Hi Julien, Hi Bertrand, On 17 Feb 2021, at 08:50, Julien Grall wrote: On 17/02/2021 02:00, Stefano Stabellini wrote: Hi all, Today

Re: [RFC] xen/arm: introduce XENFEAT_ARM_dom0_iommu

2021-02-17 Thread Bertrand Marquis
Hi Julien, > On 17 Feb 2021, at 16:41, Julien Grall wrote: > > > > On 17/02/2021 15:37, Bertrand Marquis wrote: >> Hi Julien, > > Hi Bertrand, > >>> On 17 Feb 2021, at 08:50, Julien Grall wrote: >>> >>> >>> >>> On 17/02/2021 02:00, Stefano Stabellini wrote: Hi all, Today Linux

Re: [RFC] xen/arm: introduce XENFEAT_ARM_dom0_iommu

2021-02-17 Thread Julien Grall
On 17/02/2021 15:37, Bertrand Marquis wrote: Hi Julien, Hi Bertrand, On 17 Feb 2021, at 08:50, Julien Grall wrote: On 17/02/2021 02:00, Stefano Stabellini wrote: Hi all, Today Linux uses the swiotlb-xen driver (drivers/xen/swiotlb-xen.c) to translate addresses for DMA operations in Do

Re: [RFC] xen/arm: introduce XENFEAT_ARM_dom0_iommu

2021-02-17 Thread Bertrand Marquis
Hi Julien, > On 17 Feb 2021, at 08:50, Julien Grall wrote: > > > > On 17/02/2021 02:00, Stefano Stabellini wrote: >> Hi all, >> Today Linux uses the swiotlb-xen driver (drivers/xen/swiotlb-xen.c) to >> translate addresses for DMA operations in Dom0. Specifically, >> swiotlb-xen is used to tran

Re: [RFC] xen/arm: introduce XENFEAT_ARM_dom0_iommu

2021-02-17 Thread Bertrand Marquis
Hi Stefano, > On 17 Feb 2021, at 02:00, Stefano Stabellini wrote: > > Hi all, > > Today Linux uses the swiotlb-xen driver (drivers/xen/swiotlb-xen.c) to > translate addresses for DMA operations in Dom0. Specifically, > swiotlb-xen is used to translate the address of a foreign page (a page > bel

Re: [RFC] xen/arm: introduce XENFEAT_ARM_dom0_iommu

2021-02-17 Thread Julien Grall
On 17/02/2021 02:00, Stefano Stabellini wrote: Hi all, Today Linux uses the swiotlb-xen driver (drivers/xen/swiotlb-xen.c) to translate addresses for DMA operations in Dom0. Specifically, swiotlb-xen is used to translate the address of a foreign page (a page belonging to a domU) mapped into D

[RFC] xen/arm: introduce XENFEAT_ARM_dom0_iommu

2021-02-16 Thread Stefano Stabellini
Hi all, Today Linux uses the swiotlb-xen driver (drivers/xen/swiotlb-xen.c) to translate addresses for DMA operations in Dom0. Specifically, swiotlb-xen is used to translate the address of a foreign page (a page belonging to a domU) mapped into Dom0 before using it for DMA. This is important beca