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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] Is there any limitation on the firmware size in Xen?
>>> On 12.05.17 at 12:06, <GLin@xxxxxxxx> wrote: > On Fri, May 12, 2017 at 07:32:49PM +1000, Jan Beulich wrote: >> >>> On 11.05.17 at 11:02, <GLin@xxxxxxxx> wrote: >> > On Thu, May 11, 2017 at 06:14:42PM +1000, Jan Beulich wrote: >> >> Note that hvmloader's main() has >> >> >> >> BUG_ON(hvm_start_info->magic != XEN_HVM_START_MAGIC_VALUE); >> >> >> >> very early, so you having got past this means the corruption >> >> occurred inside hvmloader (or at least while it was already >> >> running). Could you comment out the call to perform_tests() >> >> and try again? >> >> >> > You got it. After commenting out perform_tests(), the grub2 menu showed >> > and the system booted. >> > >> > It seems that perform_tests() cleared 0x400000~0x800000, and that's why >> > the members of hvm_start_info became 0 in my test. >> >> So could you give the below/attached patch a try? >> > It won't compile. > > tests.c: In function 'perform_tests': > tests.c:248:50: error: 'i' may be used uninitialized in this function > [-Werror=maybe-uninitialized] > if ( TEST_MEM_BASE < (uintptr_t)(modlist + i) && > ^ > cc1: all warnings being treated as errors Oops - quite obviously. No idea why neither of the two gcc versions I've built this with caught the issue. Below/attached a better one (also with a few other changes). Jan --- a/tools/firmware/hvmloader/tests.c +++ b/tools/firmware/hvmloader/tests.c @@ -19,7 +19,9 @@ * this program; If not, see <http://www.gnu.org/licenses/>. */ +#include "config.h" #include "util.h" +#include <xen/arch-x86/hvm/start_info.h> #define TEST_FAIL 0 #define TEST_PASS 1 @@ -28,11 +30,13 @@ /* * Memory layout during tests: * 4MB to 8MB is cleared. - * Page directory resides at 8MB. - * 4 page table pages reside at 8MB+4kB to 8MB+20kB. - * Pagetables identity-map 0-16MB, except 4kB at va 6MB maps to pa 5MB. + * Page directory resides at 4MB. + * 2 page table pages reside at 4MB+4kB to 4MB+12kB. + * Pagetables identity-map 0-8MB, except 4kB at va 6MB maps to pa 5MB. */ -#define PD_START (8ul << 20) +#define TEST_MEM_BASE (4ul << 20) +#define TEST_MEM_SIZE (4ul << 20) +#define PD_START TEST_MEM_BASE #define PT_START (PD_START + 4096) static void setup_paging(void) @@ -41,10 +45,10 @@ static void setup_paging(void) uint32_t *pt = (uint32_t *)PT_START; uint32_t i; - /* Identity map 0-16MB. */ - for ( i = 0; i < 4; i++ ) + /* Identity map 0-8MB. */ + for ( i = 0; i < 2; i++ ) pd[i] = (unsigned long)pt + (i<<12) + 3; - for ( i = 0; i < (4*1024); i++ ) + for ( i = 0; i < 2 * 1024; i++ ) pt[i] = (i << 12) + 3; /* Page at virtual 6MB maps to physical 5MB. */ @@ -112,7 +116,7 @@ static int rep_io_test(void) stop_paging(); i = 0; - for ( p = (uint32_t *)0x400000ul; p < (uint32_t *)0x700000ul; p++ ) + for ( p = (uint32_t *)0x4ff000ul; p < (uint32_t *)0x602000ul; p++ ) { uint32_t expected = 0; if ( check[i].addr == (unsigned long)p ) @@ -144,12 +148,12 @@ static int shadow_gs_test(void) if ( !(edx & (1u<<29)) ) return TEST_SKIP; - /* Long mode pagetable setup: Identity map 0-16MB with 2MB mappings. */ + /* Long mode pagetable setup: Identity map 0-8MB with 2MB mappings. */ *pd = (unsigned long)pd + 0x1007; /* Level 4 */ pd += 512; *pd = (unsigned long)pd + 0x1007; /* Level 3 */ pd += 512; - for ( i = 0; i < 8; i++ ) /* Level 2 */ + for ( i = 0; i < 4; i++ ) /* Level 2 */ *pd++ = (i << 21) + 0x1e3; asm volatile ( @@ -191,8 +195,7 @@ static int shadow_gs_test(void) void perform_tests(void) { - int i, passed, skipped; - + unsigned int i, passed, skipped; static struct { int (* const test)(void); const char *description; @@ -204,12 +207,80 @@ void perform_tests(void) printf("Testing HVM environment:\n"); - if ( hvm_info->low_mem_pgend < 0x1000 ) + BUILD_BUG_ON(SCRATCH_PHYSICAL_ADDRESS > HVMLOADER_PHYSICAL_ADDRESS); + if ( hvm_info->low_mem_pgend < + ((TEST_MEM_BASE + TEST_MEM_SIZE) >> PAGE_SHIFT) ) + { + printf("Skipping tests due to insufficient memory (<%luMB)\n", + (TEST_MEM_BASE + TEST_MEM_SIZE) >> 20); + return; + } + + if ( (unsigned long)_end > TEST_MEM_BASE ) + { + printf("Skipping tests due to overlap with base image\n"); + return; + } + + if ( hvm_start_info->cmdline_paddr && + hvm_start_info->cmdline_paddr < TEST_MEM_BASE + TEST_MEM_SIZE && + ((hvm_start_info->cmdline_paddr + + strlen((char *)(uintptr_t)hvm_start_info->cmdline_paddr)) >= + TEST_MEM_BASE) ) + { + printf("Skipping tests due to overlap with command line\n"); + return; + } + + if ( hvm_start_info->rsdp_paddr ) { - printf("Skipping tests due to insufficient memory (<16MB)\n"); + printf("Skipping tests due to non-zero RSDP address\n"); return; } + if ( hvm_start_info->nr_modules ) + { + const struct hvm_modlist_entry *modlist = + (void *)(uintptr_t)hvm_start_info->modlist_paddr; + + if ( hvm_start_info->modlist_paddr > UINTPTR_MAX || + ((UINTPTR_MAX - (uintptr_t)modlist) / sizeof(*modlist) < + hvm_start_info->nr_modules) ) + { + printf("Skipping tests due to inaccessible module list\n"); + return; + } + + if ( TEST_MEM_BASE < (uintptr_t)(modlist + + hvm_start_info->nr_modules) && + (uintptr_t)modlist < TEST_MEM_BASE + TEST_MEM_SIZE ) + { + printf("Skipping tests due to overlap with module list\n"); + return; + } + + for ( i = 0; i < hvm_start_info->nr_modules; ++i ) + { + if ( TEST_MEM_BASE < modlist[i].paddr + modlist[i].size && + modlist[i].paddr < TEST_MEM_BASE + TEST_MEM_SIZE ) + { + printf("Skipping tests due to overlap with module %u\n", i); + return; + } + + if ( modlist[i].cmdline_paddr && + modlist[i].cmdline_paddr < TEST_MEM_BASE + TEST_MEM_SIZE && + ((modlist[i].cmdline_paddr + + strlen((char *)(uintptr_t)modlist[i].cmdline_paddr)) >= + TEST_MEM_BASE) ) + { + printf("Skipping tests due to overlap with module %u cmdline\n", + i); + return; + } + } + } + passed = skipped = 0; for ( i = 0; tests[i].test; i++ ) { Attachment:
hvmloader-constrain-tests.patch _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx https://lists.xen.org/xen-devel
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