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Re: [Xen-devel] [V8 PATCH 2/8] pvh dom0: construct_dom0 changes

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 
+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?


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