Re: [Xen-devel] [PATCH v2 1/5] libxc: remove allocate member from struct xc_dom_image
On 10/02/2015 03:01 PM, Ian Campbell wrote: On Fri, 2015-10-02 at 07:49 +0200, Juergen Gross wrote: The allocate() callback in struct xc_dom_image is never set. Remove it. Signed-off-by: Juergen GrossAcked-by: Ian Jackson This breaks the stubdom build: kexec.c: In function ‘kexec’: kexec.c:221:78: warning: taking address of expression of type ‘void’ xen_pfn_t boot_page_mfn = virt_to_mfn(&_boot_page); ^ kexec.c:230:8: error: ‘struct xc_dom_image’ has no member named ‘allocate’ dom->allocate = kexec_allocate; ^ kexec.c:318:60: warning: taking address of expression of type ‘void’ virt_to_mfn(&_boot_page)); ^ Makefile:79: recipe for target '/local/scratch/ianc/devel/committer-amd64.git/stubdom/grub-x86_64/kexec.o' failed On i386 too. And in fact that hook looks useful in that context, so either it needs to stay of stubdom kexec needs changing to work some other way. Too bad. I wanted to remove the allocate callback as it will conflict with the allocations of memory outside the initial default mapping. Just to make sure I understand this correctly: stubdom is used in this context to support grub running as a pv domain capable to start another pv domain. So as long as stubdom doesn't support mapping the p2m list outside the default mapping it makes no sense to support this feature for any domain started via stubdom/grub (the main reason to use this feature is the support of huge memory causing the p2m list to exceed the available virtual address space of the default mapping). So the easy solution would be to not support initrd and p2m outside the default mapping when the allocate callback is set. Do you think this solution is okay? Juergen ___ Xen-devel mailing list Xen-devel@lists.xen.org http://lists.xen.org/xen-devel
Re: [Xen-devel] [PATCH v2 1/5] libxc: remove allocate member from struct xc_dom_image
On Fri, 2015-10-02 at 07:49 +0200, Juergen Gross wrote: > The allocate() callback in struct xc_dom_image is never set. Remove it. > > Signed-off-by: Juergen Gross> Acked-by: Ian Jackson This breaks the stubdom build: kexec.c: In function ‘kexec’: kexec.c:221:78: warning: taking address of expression of type ‘void’ xen_pfn_t boot_page_mfn = virt_to_mfn(&_boot_page); ^ kexec.c:230:8: error: ‘struct xc_dom_image’ has no member named ‘allocate’ dom->allocate = kexec_allocate; ^ kexec.c:318:60: warning: taking address of expression of type ‘void’ virt_to_mfn(&_boot_page)); ^ Makefile:79: recipe for target '/local/scratch/ianc/devel/committer-amd64.git/stubdom/grub-x86_64/kexec.o' failed On i386 too. And in fact that hook looks useful in that context, so either it needs to stay of stubdom kexec needs changing to work some other way. Ian. ___ Xen-devel mailing list Xen-devel@lists.xen.org http://lists.xen.org/xen-devel
Re: [Xen-devel] [PATCH v2 1/5] libxc: remove allocate member from struct xc_dom_image
On 10/02/2015 04:47 PM, Ian Campbell wrote: On Fri, 2015-10-02 at 16:25 +0200, Juergen Gross wrote: On 10/02/2015 03:01 PM, Ian Campbell wrote: On Fri, 2015-10-02 at 07:49 +0200, Juergen Gross wrote: The allocate() callback in struct xc_dom_image is never set. Remove it. Signed-off-by: Juergen GrossAcked-by: Ian Jackson This breaks the stubdom build: kexec.c: In function ‘kexec’: kexec.c:221:78: warning: taking address of expression of type ‘void’ xen_pfn_t boot_page_mfn = virt_to_mfn(&_boot_page); ^ kexec.c:230:8: error: ‘struct xc_dom_image’ has no member named ‘allocate’ dom->allocate = kexec_allocate; ^ kexec.c:318:60: warning: taking address of expression of type ‘void’ virt_to_mfn(&_boot_page)); ^ Makefile:79: recipe for target '/local/scratch/ianc/devel/committer -amd64.git/stubdom/grub-x86_64/kexec.o' failed On i386 too. And in fact that hook looks useful in that context, so either it needs to stay of stubdom kexec needs changing to work some other way. Too bad. I wanted to remove the allocate callback as it will conflict with the allocations of memory outside the initial default mapping. Just to make sure I understand this correctly: stubdom is used in this context to support grub running as a pv domain capable to start another pv domain. Correct. So as long as stubdom doesn't support mapping the p2m list outside the default mapping it makes no sense to support this feature for any domain started via stubdom/grub (the main reason to use this feature is the support of huge memory causing the p2m list to exceed the available virtual address space of the default mapping). By "default mapping" you mean the mapping established by the domain builder which made the domain, as distinct from any mapping which the guest kernel might establish by itself later, right? Yes. I'm not sure that there is any link between the stubdomain's own p2m and the default mapping of that and the p2m which it is building for use of the domain it is going to kexec and the default mappings of that p2m-to-be from the PoV of the to-be-kexec'd guest kernel. I just checked it again. Initially I thought stubdom would have the same limitations as Linux regarding the p2m size. But this is not true, as stubdom's virt_base is 0, while Linux is using 8000. I'm not sure how kexec operates in this regard. So the easy solution would be to not support initrd and p2m outside the default mapping when the allocate callback is set. Do you think this solution is okay? Irrespective of the above just not supporting this mode would be one way to avoid the issue. It would make domains using pvgrub1 have different limitations than domains built directly. IOW users will have to trade off the security benefits of pvgrub vs the size of the domain they wish to build, which is a shame. Hmm, maybe it's possible to add the support to stubdom. With the limit of the p2m size not hitting stubdom it might be rather easy. I'll try it. On the other hand pvgrub2 now exists as a separate (out of tree, it's in grub.git) thing anyway which doesn't use this domain builder at all AFAIK and that's the one I expect people are using going forward anyway. Hmm, another place where huge domain support is to be added, I guess. Juergen ___ Xen-devel mailing list Xen-devel@lists.xen.org http://lists.xen.org/xen-devel
[Xen-devel] [PATCH v2 1/5] libxc: remove allocate member from struct xc_dom_image
The allocate() callback in struct xc_dom_image is never set. Remove it. Signed-off-by: Juergen GrossAcked-by: Ian Jackson --- tools/libxc/include/xc_dom.h | 2 -- tools/libxc/xc_dom_core.c| 4 2 files changed, 6 deletions(-) diff --git a/tools/libxc/include/xc_dom.h b/tools/libxc/include/xc_dom.h index 602c5cd..5eeff15 100644 --- a/tools/libxc/include/xc_dom.h +++ b/tools/libxc/include/xc_dom.h @@ -175,8 +175,6 @@ struct xc_dom_image { /* kernel loader */ struct xc_dom_arch *arch_hooks; -/* allocate up to virt_alloc_end */ -int (*allocate) (struct xc_dom_image * dom, xen_vaddr_t up_to); }; /* --- pluggable kernel loader - */ diff --git a/tools/libxc/xc_dom_core.c b/tools/libxc/xc_dom_core.c index fbe4464..b510bbd 100644 --- a/tools/libxc/xc_dom_core.c +++ b/tools/libxc/xc_dom_core.c @@ -579,8 +579,6 @@ int xc_dom_alloc_segment(struct xc_dom_image *dom, seg->vend = start + pages * page_size; dom->virt_alloc_end = seg->vend; -if (dom->allocate) -dom->allocate(dom, dom->virt_alloc_end); DOMPRINTF("%-20s: %-12s : 0x%" PRIx64 " -> 0x%" PRIx64 " (pfn 0x%" PRIpfn " + 0x%" PRIpfn " pages)", @@ -603,8 +601,6 @@ int xc_dom_alloc_page(struct xc_dom_image *dom, char *name) start = dom->virt_alloc_end; dom->virt_alloc_end += page_size; -if (dom->allocate) -dom->allocate(dom, dom->virt_alloc_end); pfn = (start - dom->parms.virt_base) / page_size; DOMPRINTF("%-20s: %-12s : 0x%" PRIx64 " (pfn 0x%" PRIpfn ")", -- 2.1.4 ___ Xen-devel mailing list Xen-devel@lists.xen.org http://lists.xen.org/xen-devel