Re: [PATCH] iommu/vt-d: Remove unnecassary qi clflushes

2016-07-13 Thread Joerg Roedel
On Fri, Jun 24, 2016 at 06:13:14AM -0700, Nadav Amit wrote: > According to the manual: "Hardware access to ... invalidation queue ... > are always coherent." > > Remove unnecassary clflushes accordingly. > > Signed-off-by: Nadav Amit Applied, thanks.

Re: [PATCH] iommu/vt-d: Remove unnecassary qi clflushes

2016-07-05 Thread Paolo Bonzini
On 05/07/2016 18:50, Nadav Amit wrote: > Paolo Bonzini wrote: > >> >> >> On 05/07/2016 18:27, Nadav Amit wrote: Although such hardware is old, there are some hypervisors that do not set the ecap.coherency of emulated IOMMUs. Yes, it is unwise, but there is no

Re: [PATCH] iommu/vt-d: Remove unnecassary qi clflushes

2016-07-05 Thread Nadav Amit
Paolo Bonzini wrote: > > > On 05/07/2016 18:27, Nadav Amit wrote: >>> Although such hardware is old, there are some hypervisors that do not set >>> the ecap.coherency of emulated IOMMUs. Yes, it is unwise, but there is no >>> reason to further punish these hypervisors. >

Re: [PATCH] iommu/vt-d: Remove unnecassary qi clflushes

2016-07-05 Thread Paolo Bonzini
On 05/07/2016 18:27, Nadav Amit wrote: >> Although such hardware is old, there are some hypervisors that do not set >> the ecap.coherency of emulated IOMMUs. Yes, it is unwise, but there is no >> reason to further punish these hypervisors. QEMU will need the kernel to respect ecap.coherency in

Re: [PATCH] iommu/vt-d: Remove unnecassary qi clflushes

2016-07-05 Thread Nadav Amit
Nadav Amit wrote: > Joerg Roedel wrote: > >> On Fri, Jun 24, 2016 at 06:13:14AM -0700, Nadav Amit wrote: >>> According to the manual: "Hardware access to ... invalidation queue ... >>> are always coherent." >>> >>> Remove unnecassary clflushes

Re: [PATCH] iommu/vt-d: Remove unnecassary qi clflushes

2016-06-27 Thread Nadav Amit
Joerg Roedel wrote: > On Fri, Jun 24, 2016 at 06:13:14AM -0700, Nadav Amit wrote: >> According to the manual: "Hardware access to ... invalidation queue ... >> are always coherent." >> >> Remove unnecassary clflushes accordingly. > > It is one thing what the spec says and

Re: [PATCH] iommu/vt-d: Remove unnecassary qi clflushes

2016-06-27 Thread Joerg Roedel
On Fri, Jun 24, 2016 at 06:13:14AM -0700, Nadav Amit wrote: > According to the manual: "Hardware access to ... invalidation queue ... > are always coherent." > > Remove unnecassary clflushes accordingly. It is one thing what the spec says and another how hardware really behaves. Have you tested

[PATCH] iommu/vt-d: Remove unnecassary qi clflushes

2016-06-24 Thread Nadav Amit
According to the manual: "Hardware access to ... invalidation queue ... are always coherent." Remove unnecassary clflushes accordingly. Signed-off-by: Nadav Amit --- Build-tested since I do not have an IOMMU that does not support coherency. --- drivers/iommu/dmar.c | 5