[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH v2 1/2] xen: introduce arch_iommu_grant_(un)map_page
On 24/07/14 12:16, Stefano Stabellini wrote: On Thu, 24 Jul 2014, Julien Grall wrote:On 24/07/14 12:07, Stefano Stabellini wrote:On Thu, 24 Jul 2014, Julien Grall wrote:Hi Stefano, The Title of the commit message is now wrong.Thanks, I didn't notice.On 23/07/14 18:19, Stefano Stabellini wrote:Introduce two arch specific functions to create a new p2m mapping of granted pages at pfn == mfn. The x86 implementation just returns ENOSYS. Signed-off-by: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx> --- xen/arch/arm/p2m.c | 19 +++++++++++++++++++ xen/include/asm-arm/p2m.h | 4 ++++ xen/include/asm-x86/p2m.h | 13 +++++++++++++ 3 files changed, 36 insertions(+) diff --git a/xen/arch/arm/p2m.c b/xen/arch/arm/p2m.c index 9960e17..c38af59 100644 --- a/xen/arch/arm/p2m.c +++ b/xen/arch/arm/p2m.c @@ -555,6 +555,25 @@ void guest_physmap_remove_page(struct domain *d, pfn_to_paddr(mfn), MATTR_MEM, p2m_invalid); } +int arch_grant_map_page_identity(struct domain *d, unsigned long frame, + bool_t writeable) +{ + p2m_type_t t; + + if ( writeable ) + t = p2m_ram_rw; + else + t = p2m_ram_ro;This is not the right p2m type to use here. p2m_ram_{rw,ro} allow foreign mapping. So another guest could access to the grant. I would use p2m_iommu_map_{rw,ro}.I see. I'll make the change and add a comment to explain why we are using p2m_iommu types for non-iommu related mappings.The code to add the 1:1 mapping for the SMMU is very ugly. I was wondering if we could drop the iommu_map_page callback and directly use arch_grant_map_page_identity in all the case. It would avoid the if/else in the grant code.Thing is arch_grant_map_page_identity has nothing to do with IOMMUs. It gets confusing, especially on x86 where people don't know why we need this. The if/else is ugly but clearer. See also the previous email exchange with Jan. Ok. So could we call this function from iommu_map_page on the SMMU? It would at least avoid duplicating the code? Regards, -- Julien Grall _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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