From: Juergen Gross Date: Tue, 26 Sep 2017 12:02:56 +0000 (+0200) Subject: libxc: remove stale error check for domain size in xc_sr_save_x86_hvm.c X-Git-Tag: archive/raspbian/4.11.1-1+rpi1~1^2~66^2~1063 X-Git-Url: https://dgit.raspbian.org/?a=commitdiff_plain;h=26a896cde21c6d03de367190034fcc150b1bf2d8;p=xen.git libxc: remove stale error check for domain size in xc_sr_save_x86_hvm.c Long ago domains to be saved were limited to 1TB size due to the migration stream v1 limitations which used a 32 bit value for the PFN and the frame type (4 bits) leaving only 28 bits for the PFN. Migration stream V2 uses a 64 bit value for this purpose, so there is no need to refuse saving (or migrating) domains larger than 1 TB. For 32 bit toolstacks there is still a size limit, as domains larger than about 1TB will lead to an exhausted virtual address space of the saving process. So keep the test for 32 bit, but don't base it on the page type macros. As a migration could lead to the situation where a 32 bit toolstack would have to handle such a large domain (in case the sending side is 64 bit) the same test should be added for restoring a domain. Signed-off-by: Juergen Gross Acked-by: Wei Liu Release-acked-by: Julien Grall --- diff --git a/tools/libxc/xc_sr_restore_x86_hvm.c b/tools/libxc/xc_sr_restore_x86_hvm.c index 1dca85354a..227c48553e 100644 --- a/tools/libxc/xc_sr_restore_x86_hvm.c +++ b/tools/libxc/xc_sr_restore_x86_hvm.c @@ -148,6 +148,15 @@ static int x86_hvm_setup(struct xc_sr_context *ctx) ctx->restore.guest_page_size); return -1; } +#ifdef __i386__ + /* Very large domains (> 1TB) will exhaust virtual address space. */ + if ( ctx->restore.p2m_size > 0x0fffffff ) + { + errno = E2BIG; + PERROR("Cannot restore this big a guest"); + return -1; + } +#endif return 0; } diff --git a/tools/libxc/xc_sr_save_x86_hvm.c b/tools/libxc/xc_sr_save_x86_hvm.c index e17bb59146..97a8c49807 100644 --- a/tools/libxc/xc_sr_save_x86_hvm.c +++ b/tools/libxc/xc_sr_save_x86_hvm.c @@ -148,12 +148,15 @@ static int x86_hvm_setup(struct xc_sr_context *ctx) PERROR("Unable to obtain the guest p2m size"); return -1; } - if ( nr_pfns > ~XEN_DOMCTL_PFINFO_LTAB_MASK ) +#ifdef __i386__ + /* Very large domains (> 1TB) will exhaust virtual address space. */ + if ( nr_pfns > 0x0fffffff ) { errno = E2BIG; PERROR("Cannot save this big a guest"); return -1; } +#endif ctx->save.p2m_size = nr_pfns;