Messages in this thread | | | Date | Thu, 13 Nov 2014 10:53:22 +0000 | From | "Jan Beulich" <> | Subject | Re: [Xen-devel] [PATCH 3/3] x86/xen: use the maximum MFN to calculate the required DMA mask |
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>>> On 13.11.14 at 11:38, <andrew.cooper3@citrix.com> wrote: > On 12/11/14 15:55, Jan Beulich wrote: >>>>> On 12.11.14 at 16:25, <david.vrabel@citrix.com> wrote: >>> +u64 >>> +xen_swiotlb_get_required_mask(struct device *dev) >>> +{ >>> + u64 max_mfn; >>> + >>> + max_mfn = HYPERVISOR_memory_op(XENMEM_maximum_ram_page, NULL); >>> + >>> + return DMA_BIT_MASK(fls64(max_mfn << PAGE_SHIFT) + 1); >>> +} >> The value the hypercall returns is exclusive and an unsigned long. > > All hypercalls return long, despite lack of clarity, or in some cases, > documentation to the contrary.
The emphasis wasn't on "unsigned" but on "long". But see also my later reply to that same mail.
Jan
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