[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [V8 PATCH 2/8] pvh dom0: construct_dom0 changes
On 04/05/2014 01:53 AM, Mukesh Rathor wrote: On Thu, 27 Mar 2014 16:30:37 +0100 Tim Deegan <tim@xxxxxxx> wrote:At 15:04 +0000 on 27 Mar (1395929085), Jan Beulich wrote:On 27.03.14 at 11:55, <george.dunlap@xxxxxxxxxxxxx> wrote:On 03/27/2014 10:14 AM, Jan Beulich wrote:On 26.03.14 at 20:05, <george.dunlap@xxxxxxxxxxxxx> wrote:--- a/xen/arch/x86/mm/hap/hap.c +++ b/xen/arch/x86/mm/hap/hap.c @@ -589,6 +589,21 @@ int hap_domctl(struct domain *d, xen_domctl_shadow_op_t*sc,} }+void __init hap_set_pvh_alloc_for_dom0(struct domain *d,+ unsigned long num_pages) +{ + int rc; + unsigned long memkb = num_pages * (PAGE_SIZE / 1024); + + /* Copied from: libxl_get_required_shadow_memory() */ + memkb = 4 * (256 * d->max_vcpus + 2 * (memkb / 1024)); + num_pages = ( (memkb + 1023) / 1024) << (20 - PAGE_SHIFT); + paging_lock(d); + rc = hap_set_allocation(d, num_pages, NULL); + paging_unlock(d); The calculation for how many pages of shadow memory are needed logically belongs in domain_build.c, not hap.c.Iirc it was me requesting it to be moved here, on the basis that the calculation should match the one for other domains, and hence be done alongside that for other domains. domain_build.c shouldn't carry HAP-specific knowledge imo.I thought that might be the case, which is why I apologized in advance for not reading the previous thread. The calculation should indeed match that done for other domains; however, as the comment clearly says, this calculation is done in libxl, not in Xen at all. Everything done to build dom0 in Xen which corresponds to things done by the toolstack to build a domU logically belongs in domain_build.c. Putting it in hap.c would be wrong in any case; what would you do when we enable shadow mode for HAP dom0?The function calls hap_set_allocation(), so it's already HAP-specific.It really ought to be calling a paging_set_allocation() wrapper; there's nothing _inherently_ HAP-specific about PVH. Right now that wrapper doesn't exist, because that path goes via paging_domctl() for other domains.Correct, PVH requires HAP at present, and I like when the code makes that clear. In general, my approach is to make change in future when demanded, thus, when shadow is added, it can be rearranged with small effort. Anyways, I'm flexible. Jan, final word: Leave it as is (my first pref), move to domain_build.c, or put a wrapper(my last preference) ? I'm fine with the code in domain_build.c calling hap_set_allocation() directly for the time being, and implementing a paging_set_allocation() wrapper later; but I think the code doing the calculation should be in domain_build.c. -George _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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