[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH v4.2] libxc: Defer initialization of start_page for HVM guests
On 07/01/16 23:19, Boris Ostrovsky wrote: > With commit 8c45adec18e0 ("libxc: create unmapped initrd in domain > builder if supported") location of ramdisk may not be available to > HVMlite guests by the time alloc_magic_pages_hvm() is invoked if the > guest supports unmapped initrd. > > So let's move ramdisk info initialization (along with a few other > operations that are not directly related to allocating magic/special > pages) from alloc_magic_pages_hvm() to bootlate_hvm(). > > Since we now split allocation and mapping of the start_info segment > let's stash it, along with cmdline length, in xc_dom_image so that we > can check whether we are mapping correctly-sized range. > > We can also stop using xc_dom_image.start_info_pfn and leave it for > PV(H) guests only. > > Signed-off-by: Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx> > --- > v4: > * See the last two paragraphs from commit message above > > v4.1: > * Inverted testing of start_info_size in bootlate_hvm(). > > v4.2 > * <facepalm> Actually do what I said I'd do in 4.1 > > tools/libxc/include/xc_dom.h | 2 + > tools/libxc/xc_dom_x86.c | 140 +++++++++++++++++++++++------------------ > 2 files changed, 80 insertions(+), 62 deletions(-) > > diff --git a/tools/libxc/include/xc_dom.h b/tools/libxc/include/xc_dom.h > index 2460818..cac4698 100644 > --- a/tools/libxc/include/xc_dom.h > +++ b/tools/libxc/include/xc_dom.h > @@ -71,6 +71,7 @@ struct xc_dom_image { > > /* arguments and parameters */ > char *cmdline; > + size_t cmdline_size; > uint32_t f_requested[XENFEAT_NR_SUBMAPS]; > > /* info from (elf) kernel image */ > @@ -91,6 +92,7 @@ struct xc_dom_image { > struct xc_dom_seg p2m_seg; > struct xc_dom_seg pgtables_seg; > struct xc_dom_seg devicetree_seg; > + struct xc_dom_seg start_info_seg; /* HVMlite only */ Instead of adding HVM specific members here, you could make use of dom.arch_private and use just a local structure defined in xc_dom_x86.c. Juergen > xen_pfn_t start_info_pfn; > xen_pfn_t console_pfn; > xen_pfn_t xenstore_pfn; > diff --git a/tools/libxc/xc_dom_x86.c b/tools/libxc/xc_dom_x86.c > index b8d2904..edf2db1 100644 > --- a/tools/libxc/xc_dom_x86.c > +++ b/tools/libxc/xc_dom_x86.c > @@ -586,23 +586,12 @@ static void build_hvm_info(void *hvm_info_page, struct > xc_dom_image *dom) > static int alloc_magic_pages_hvm(struct xc_dom_image *dom) > { > unsigned long i; > - void *hvm_info_page; > uint32_t *ident_pt, domid = dom->guest_domid; > int rc; > xen_pfn_t special_array[X86_HVM_NR_SPECIAL_PAGES]; > xen_pfn_t ioreq_server_array[NR_IOREQ_SERVER_PAGES]; > xc_interface *xch = dom->xch; > > - if ( dom->device_model ) > - { > - if ( (hvm_info_page = xc_map_foreign_range( > - xch, domid, PAGE_SIZE, PROT_READ | PROT_WRITE, > - HVM_INFO_PFN)) == NULL ) > - goto error_out; > - build_hvm_info(hvm_info_page, dom); > - munmap(hvm_info_page, PAGE_SIZE); > - } > - > /* Allocate and clear special pages. */ > for ( i = 0; i < X86_HVM_NR_SPECIAL_PAGES; i++ ) > special_array[i] = special_pfn(i); > @@ -636,65 +625,25 @@ static int alloc_magic_pages_hvm(struct xc_dom_image > *dom) > > if ( !dom->device_model ) > { > - struct xc_dom_seg seg; > - struct hvm_start_info *start_info; > - char *cmdline; > - struct hvm_modlist_entry *modlist; > - void *start_page; > - size_t cmdline_size = 0; > - size_t start_info_size = sizeof(*start_info); > + size_t start_info_size = sizeof(struct hvm_start_info); > > if ( dom->cmdline ) > { > - cmdline_size = ROUNDUP(strlen(dom->cmdline) + 1, 8); > - start_info_size += cmdline_size; > - > + dom->cmdline_size = ROUNDUP(strlen(dom->cmdline) + 1, 8); > + start_info_size += dom->cmdline_size; > } > + > + /* Limited to one module. */ > if ( dom->ramdisk_blob ) > - start_info_size += sizeof(*modlist); /* Limited to one module. */ > + start_info_size += sizeof(struct hvm_modlist_entry); > > - rc = xc_dom_alloc_segment(dom, &seg, "HVMlite start info", 0, > - start_info_size); > + rc = xc_dom_alloc_segment(dom, &dom->start_info_seg, > + "HVMlite start info", 0, start_info_size); > if ( rc != 0 ) > { > DOMPRINTF("Unable to reserve memory for the start info"); > goto out; > } > - > - start_page = xc_map_foreign_range(xch, domid, start_info_size, > - PROT_READ | PROT_WRITE, > - seg.pfn); > - if ( start_page == NULL ) > - { > - DOMPRINTF("Unable to map HVM start info page"); > - goto error_out; > - } > - > - start_info = start_page; > - cmdline = start_page + sizeof(*start_info); > - modlist = start_page + sizeof(*start_info) + cmdline_size; > - > - if ( dom->cmdline ) > - { > - strncpy(cmdline, dom->cmdline, cmdline_size); > - start_info->cmdline_paddr = (seg.pfn << PAGE_SHIFT) + > - ((uintptr_t)cmdline - (uintptr_t)start_info); > - } > - > - if ( dom->ramdisk_blob ) > - { > - modlist[0].paddr = dom->ramdisk_seg.vstart - > dom->parms.virt_base; > - modlist[0].size = dom->ramdisk_seg.vend - > dom->ramdisk_seg.vstart; > - start_info->modlist_paddr = (seg.pfn << PAGE_SHIFT) + > - ((uintptr_t)modlist - (uintptr_t)start_info); > - start_info->nr_modules = 1; > - } > - > - start_info->magic = HVM_START_MAGIC_VALUE; > - > - munmap(start_page, start_info_size); > - > - dom->start_info_pfn = seg.pfn; > } > else > { > @@ -1095,8 +1044,8 @@ static int vcpu_hvm(struct xc_dom_image *dom) > /* Set the IP. */ > bsp_ctx.cpu.rip = dom->parms.phys_entry; > > - if ( dom->start_info_pfn ) > - bsp_ctx.cpu.rbx = dom->start_info_pfn << PAGE_SHIFT; > + if ( dom->start_info_seg.pfn ) > + bsp_ctx.cpu.rbx = dom->start_info_seg.pfn << PAGE_SHIFT; > > /* Set the end descriptor. */ > bsp_ctx.end_d.typecode = HVM_SAVE_CODE(END); > @@ -1783,7 +1732,74 @@ static int alloc_pgtables_hvm(struct xc_dom_image *dom) > > static int bootlate_hvm(struct xc_dom_image *dom) > { > - DOMPRINTF("%s: doing nothing", __func__); > + uint32_t domid = dom->guest_domid; > + xc_interface *xch = dom->xch; > + > + if ( !dom->device_model ) > + { > + struct hvm_start_info *start_info; > + size_t start_info_size; > + void *start_page; > + > + start_info_size = sizeof(*start_info) + dom->cmdline_size; > + if ( dom->ramdisk_blob ) > + start_info_size += sizeof(struct hvm_modlist_entry); > + > + if ( start_info_size > > + dom->start_info_seg.pages << XC_DOM_PAGE_SHIFT(dom) ) > + { > + DOMPRINTF("Trying to map beyond start_info_seg"); > + return -1; > + } > + > + start_page = xc_map_foreign_range(xch, domid, start_info_size, > + PROT_READ | PROT_WRITE, > + dom->start_info_seg.pfn); > + if ( start_page == NULL ) > + { > + DOMPRINTF("Unable to map HVM start info page"); > + return -1; > + } > + > + start_info = start_page; > + > + if ( dom->cmdline ) > + { > + char *cmdline = start_page + sizeof(*start_info); > + > + strncpy(cmdline, dom->cmdline, dom->cmdline_size); > + start_info->cmdline_paddr = (dom->start_info_seg.pfn << > PAGE_SHIFT) + > + ((uintptr_t)cmdline - (uintptr_t)start_info); > + } > + > + if ( dom->ramdisk_blob ) > + { > + struct hvm_modlist_entry *modlist = > + start_page + sizeof(*start_info) + dom->cmdline_size; > + > + modlist[0].paddr = dom->ramdisk_seg.vstart - > dom->parms.virt_base; > + modlist[0].size = dom->ramdisk_seg.vend - > dom->ramdisk_seg.vstart; > + start_info->modlist_paddr = (dom->start_info_seg.pfn << > PAGE_SHIFT) + > + ((uintptr_t)modlist - (uintptr_t)start_info); > + start_info->nr_modules = 1; > + } > + > + start_info->magic = HVM_START_MAGIC_VALUE; > + > + munmap(start_page, start_info_size); > + } > + else > + { > + void *hvm_info_page; > + > + if ( (hvm_info_page = xc_map_foreign_range( > + xch, domid, PAGE_SIZE, PROT_READ | PROT_WRITE, > + HVM_INFO_PFN)) == NULL ) > + return -1; > + build_hvm_info(hvm_info_page, dom); > + munmap(hvm_info_page, PAGE_SIZE); > + } > + > return 0; > } > > _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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