Re: [Qemu-devel] [PATCH] intel-iommu: optimize nodmar memory regions

2019-03-14 Thread Peter Xu
On Thu, Mar 14, 2019 at 11:36:39AM +0100, Sergio Lopez wrote: > > Paolo Bonzini writes: > > > On 13/03/19 12:45, Sergio Lopez wrote: > >> > >> Peter Xu writes: > >> > >>> Previously we have per-device system memory aliases when DMAR is > >>> disabled by the system. It will slow the system down

Re: [Qemu-devel] [PATCH] intel-iommu: optimize nodmar memory regions

2019-03-14 Thread Peter Xu
On Wed, Mar 13, 2019 at 12:21:34PM +0100, Paolo Bonzini wrote: > On 13/03/19 10:43, Peter Xu wrote: > > Previously we have per-device system memory aliases when DMAR is > > disabled by the system. It will slow the system down if there are > > lots of devices especially when DMAR is disabled, becau

Re: [Qemu-devel] [PATCH] intel-iommu: optimize nodmar memory regions

2019-03-14 Thread Sergio Lopez
Paolo Bonzini writes: > On 13/03/19 12:45, Sergio Lopez wrote: >> >> Peter Xu writes: >> >>> Previously we have per-device system memory aliases when DMAR is >>> disabled by the system. It will slow the system down if there are >>> lots of devices especially when DMAR is disabled, because eac

Re: [Qemu-devel] [PATCH] intel-iommu: optimize nodmar memory regions

2019-03-13 Thread Paolo Bonzini
On 13/03/19 12:45, Sergio Lopez wrote: > > Peter Xu writes: > >> Previously we have per-device system memory aliases when DMAR is >> disabled by the system. It will slow the system down if there are >> lots of devices especially when DMAR is disabled, because each of the >> aliased system addres

Re: [Qemu-devel] [PATCH] intel-iommu: optimize nodmar memory regions

2019-03-13 Thread Sergio Lopez
Peter Xu writes: > Previously we have per-device system memory aliases when DMAR is > disabled by the system. It will slow the system down if there are > lots of devices especially when DMAR is disabled, because each of the > aliased system address space will contain O(N) slots, and rendering >

Re: [Qemu-devel] [PATCH] intel-iommu: optimize nodmar memory regions

2019-03-13 Thread Paolo Bonzini
On 13/03/19 10:43, Peter Xu wrote: > Previously we have per-device system memory aliases when DMAR is > disabled by the system. It will slow the system down if there are > lots of devices especially when DMAR is disabled, because each of the > aliased system address space will contain O(N) slots,

[Qemu-devel] [PATCH] intel-iommu: optimize nodmar memory regions

2019-03-13 Thread Peter Xu
Previously we have per-device system memory aliases when DMAR is disabled by the system. It will slow the system down if there are lots of devices especially when DMAR is disabled, because each of the aliased system address space will contain O(N) slots, and rendering such N address spaces will be