Messages in this thread | | | Date | Tue, 07 Jul 2015 16:42:37 -0400 | From | Boris Ostrovsky <> | Subject | Re: [PATCH 4/6] xen/x86/pvh: Set up descriptors for 32-bit PVH guests |
| |
On 07/07/2015 03:54 PM, Konrad Rzeszutek Wilk wrote: > On Mon, Jul 06, 2015 at 11:34:23PM -0400, Boris Ostrovsky wrote: >> Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> >> --- >> arch/x86/xen/enlighten.c | 16 ++++++++++++---- >> 1 file changed, 12 insertions(+), 4 deletions(-) >> >> diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c >> index 0b95c9b..7953e68 100644 >> --- a/arch/x86/xen/enlighten.c >> +++ b/arch/x86/xen/enlighten.c >> @@ -1362,12 +1362,12 @@ static void __init xen_boot_params_init_edd(void) >> static void __ref xen_setup_gdt(int cpu) >> { >> if (xen_feature(XENFEAT_auto_translated_physmap)) { >> -#ifdef CONFIG_X86_64 >> unsigned long dummy; >> >> - load_percpu_segment(cpu); /* We need to access per-cpu area */ >> + setup_stack_canary_segment(cpu); >> switch_to_new_gdt(cpu); /* GDT and GS set */ >> >> +#ifdef CONFIG_X86_64 >> /* We are switching of the Xen provided GDT to our HVM mode >> * GDT. The new GDT has __KERNEL_CS with CS.L = 1 >> * and we are jumping to reload it. >> @@ -1392,8 +1392,16 @@ static void __ref xen_setup_gdt(int cpu) >> loadsegment(ds, 0); >> loadsegment(fs, 0); >> #else >> - /* PVH: TODO Implement. */ >> - BUG(); >> + asm volatile ("ljmp %1,$1f\n" >> + "1:\n" >> + "movl %2,%0\n" >> + "movl %0,%%ss\n" >> + "movl %3,%0\n" >> + "movl %0,%%ds\n" >> + "movl %0,%%es\n" >> + : "=&r" (dummy) >> + : "i" (__KERNEL_CS), "i" (__KERNEL_DS), >> + "i" (__USER_DS)); >> #endif > Which comes out to: > ljmp $96,$1f #[KERNEL_CS] > 1: > movl $104,%eax #, dummy #[KERNEL_DS] > movl %eax,%ss # dummy > movl $123,%eax #, dummy #[USER_DS] > movl %eax,%ds # dummy > movl %eax,%es # dummy > > And that looks right
Actually, now that look at this again I think I should just use loadsegment(), just like 64-bit code above.
-boris
> > Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> > >> return; /* PVH does not need any PV GDT ops. */ >> } >> -- >> 1.8.1.4 >>
| |