On Thu, Jan 17, 2013 at 11:20:43AM +0800, Xiao Guangrong wrote: > On 01/17/2013 03:07 AM, Marcelo Tosatti wrote: > > On Fri, Jan 11, 2013 at 06:25:18PM +0900, Takuya Yoshikawa wrote: > >> Patches 1 to 3 are trivial. > >> > >> Patch 4 is the main cause of the increased lines, but I think the new > >> code makes it easier to understand why each condition in > >> __kvm_set_memory_region() is there. > >> > >> If you don't agree with patch 4, please consider taking the rest of the > >> series at this time. > >> > >> Takuya Yoshikawa (4): > >> KVM: set_memory_region: Don't jump to out_free unnecessarily > >> KVM: set_memory_region: Don't check for overlaps unless we create or move a slot > >> KVM: set_memory_region: Remove unnecessary variable memslot > >> KVM: set_memory_region: Identify the requested change explicitly > >> > >> virt/kvm/kvm_main.c | 94 ++++++++++++++++++++++++++++++++------------------- > >> 1 files changed, 59 insertions(+), 35 deletions(-) > >> > >> -- > >> 1.7.5.4 > > > > Reviewed-by: Marcelo Tosatti <mtosatti@xxxxxxxxxx> > > > > BTW, while at it, its probably worthwhile to restrict flags > > modifications: change from flags = 0 to flags = read-only is > > incomplete. Xiao, should it be allowed only during creation? > > Will Readonly memory be used for VM-mem-sharing in the future? > I remember you mentioned about mem-sharing things before. ;) > > Actually, It is safe on KVM MMU because all the gfns in the slot > can become readonly after calling __kvm_set_memory_region. It is > unsafe on IOMMU, what need to be fixed is unmapping gfns on IOMMU > when the flag is changed. Which means if we allow changing flags from 0 to read_only or back we need to call kvm_iommu_map_pages() when flags change. BTW as far as I see currently IOMMU maps everything as read/write not matter what flags say. Looks like a bug. Alex? -- Gleb. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
