> -----Original Message----- > From: Eric Auger <[email protected]> > Sent: 26 May 2026 10:31 > To: Shameer Kolothum Thodi <[email protected]>; qemu- > [email protected]; [email protected] > Cc: [email protected]; [email protected]; [email protected]; Nicolin > Chen <[email protected]>; Nathan Chen <[email protected]>; Matt > Ochs <[email protected]>; Jiandi An <[email protected]>; Jason Gunthorpe > <[email protected]>; [email protected]; Krishnakant Jaju > <[email protected]>; [email protected]; Peter Xu <[email protected]>; > Philippe Mathieu-Daudé <[email protected]> > Subject: Re: [PATCH v5 26/32] system/physmem: Add > qemu_ram_backend_pagesize_min() helper > > External email: Use caution opening links or attachments > > > On 5/19/26 12:37 PM, Shameer Kolothum wrote: > > Some hardware accelerators DMA directly to the host physical address > s/DMA/perform DMA accesses > > of a guest-resident buffer (e.g. set up via IOMMUFD). The HPA is > > contiguous only within a single host backing page; a buffer larger > > than the smallest backing page in use may span non-contiguous host > > pages and fault. > > > > Introduce qemu_ram_backend_pagesize_min(), which returns the smallest > > page size among RAM regions backed by a memory-backend object. Falls > Don't you have means to be more precise? I mean you know the GPA of the > cmdq, can't you make sure it belongs to a specific ramblock and check > its min page_size?
As you noted in the next patch we don’t have GPA at the time of init. > > By the way there is find_min_backend_pagesize() that exists. Can't you > reuse that? Ah.. Thanks!. That looks like is doing the same thing. And we also have warpper that uses it, qemu_minrampagesize(). I will get rid of this patch and use that instead. Thanks, Shameer
