On 19/10/2018 14:17, Daniel Kiper wrote: > On Tue, Oct 09, 2018 at 01:03:08PM +0200, Juergen Gross wrote: >> Add the code for the Xen PVH mode boot entry. >> >> Signed-off-by: Juergen Gross <jgr...@suse.com> >> --- >> grub-core/kern/i386/xen/startup_pvh.S | 50 >> +++++++++++++++++++++++++++++++++++ >> 1 file changed, 50 insertions(+) >> >> diff --git a/grub-core/kern/i386/xen/startup_pvh.S >> b/grub-core/kern/i386/xen/startup_pvh.S >> index e18ee5b31..0ddb63b31 100644 >> --- a/grub-core/kern/i386/xen/startup_pvh.S >> +++ b/grub-core/kern/i386/xen/startup_pvh.S >> @@ -19,11 +19,61 @@ >> >> #include <config.h> >> #include <grub/symbol.h> >> +#include <grub/machine/memory.h> >> >> .file "startup_pvh.S" >> .text >> + .globl start, _start >> + .code32 >> >> +start: >> +_start: >> + cld >> + lgdt gdtdesc >> + ljmp $GRUB_MEMORY_MACHINE_PROT_MODE_CSEG, $1f >> +1: >> + movl $GRUB_MEMORY_MACHINE_PROT_MODE_DSEG, %eax >> + mov %eax, %ds >> + mov %eax, %es >> + mov %eax, %ss > > Should not you load null descriptor into %fs and %gs? > Just in case...
Hmm, if you want I can do that, sure. > >> + leal LOCAL(stack_end), %esp >> + >> + /* Save address of start info structure. */ >> + mov %ebx, pvh_start_info >> + call EXT_C(grub_main) >> + /* Doesn't return. */ >> + >> + .p2align 3 >> +gdt: >> + .word 0, 0 >> + .byte 0, 0, 0, 0 >> + >> + /* -- code segment -- >> + * base = 0x00000000, limit = 0xFFFFF (4 KiB Granularity), present >> + * type = 32bit code execute/read, DPL = 0 >> + */ >> + .word 0xFFFF, 0 >> + .byte 0, 0x9A, 0xCF, 0 >> + >> + /* -- data segment -- >> + * base = 0x00000000, limit 0xFFFFF (4 KiB Granularity), present >> + * type = 32 bit data read/write, DPL = 0 >> + */ >> + .word 0xFFFF, 0 >> + .byte 0, 0x92, 0xCF, 0 >> + >> + .p2align 3 >> +/* this is the GDT descriptor */ >> +gdtdesc: >> + .word 0x17 /* limit */ >> + .long gdt /* addr */ >> + >> + .p2align 2 >> /* Saved pointer to start info structure. */ >> .globl pvh_start_info >> pvh_start_info: >> .long 0 >> + >> + .bss >> + .space (1 << 22) > > Hmmm... Why do we need 4 MiB here? If this is really needed then it begs for > a comment. And I would like to see a constant instead of plain number here. This is just copied from xen/startup.S I can reduce it to something near GRUB_MEMORY_MACHINE_PROT_STACK_SIZE (about 64kB). Juergen _______________________________________________ Xen-devel mailing list Xen-devel@lists.xenproject.org https://lists.xenproject.org/mailman/listinfo/xen-devel
