Re: [Xen-devel] [PATCH] xen-mapcache: Fix the bug when overlapping emulated DMA operations may cause inconsistency in guest memory mappings

2017-07-21 Thread Stefano Stabellini
On Thu, 20 Jul 2017, Alexey G wrote: > On Wed, 19 Jul 2017 11:00:26 -0700 (PDT) > Stefano Stabellini wrote: > > > My expectation is that unlocked mappings are much more frequent than > > locked mappings. Also, I expect that only very rarely we'll be able to > > reuse

Re: [Xen-devel] [PATCH] xen-mapcache: Fix the bug when overlapping emulated DMA operations may cause inconsistency in guest memory mappings

2017-07-20 Thread Stefano Stabellini
On Thu, 20 Jul 2017, Alexey G wrote: > On Wed, 19 Jul 2017 11:00:26 -0700 (PDT) > Stefano Stabellini wrote: > > > My expectation is that unlocked mappings are much more frequent than > > locked mappings. Also, I expect that only very rarely we'll be able to > > reuse

Re: [Xen-devel] [PATCH] xen-mapcache: Fix the bug when overlapping emulated DMA operations may cause inconsistency in guest memory mappings

2017-07-19 Thread Alexey G
On Wed, 19 Jul 2017 11:00:26 -0700 (PDT) Stefano Stabellini wrote: > My expectation is that unlocked mappings are much more frequent than > locked mappings. Also, I expect that only very rarely we'll be able to > reuse locked mappings. Over the course of a VM lifetime, it

Re: [Xen-devel] [PATCH] xen-mapcache: Fix the bug when overlapping emulated DMA operations may cause inconsistency in guest memory mappings

2017-07-19 Thread Stefano Stabellini
On Wed, 19 Jul 2017, Alexey G wrote: > Stefano, > > On Tue, 18 Jul 2017 15:17:25 -0700 (PDT) > Stefano Stabellini wrote: > > > > The patch modifies the behavior in which MapCacheEntry's are added to > > > the list, avoiding duplicates. > > > > I take that the idea is

Re: [Xen-devel] [PATCH] xen-mapcache: Fix the bug when overlapping emulated DMA operations may cause inconsistency in guest memory mappings

2017-07-19 Thread Alexey G
Stefano, On Tue, 18 Jul 2017 15:17:25 -0700 (PDT) Stefano Stabellini wrote: > > The patch modifies the behavior in which MapCacheEntry's are added to > > the list, avoiding duplicates. > > I take that the idea is to always go through the whole list to check for >

Re: [Xen-devel] [PATCH] xen-mapcache: Fix the bug when overlapping emulated DMA operations may cause inconsistency in guest memory mappings

2017-07-18 Thread Stefano Stabellini
On Tue, 11 Jul 2017, Alexey G wrote: > Under certain circumstances normal xen-mapcache functioning may be broken > by guest's actions. This may lead to either QEMU performing exit() due to > a caught bad pointer (and with QEMU process gone the guest domain simply > appears hung afterwards) or

[Xen-devel] [PATCH] xen-mapcache: Fix the bug when overlapping emulated DMA operations may cause inconsistency in guest memory mappings

2017-07-10 Thread Alexey G
Under certain circumstances normal xen-mapcache functioning may be broken by guest's actions. This may lead to either QEMU performing exit() due to a caught bad pointer (and with QEMU process gone the guest domain simply appears hung afterwards) or actual use of the incorrect pointer inside QEMU