| Message ID | 1480100691-5589-1-git-send-email-andrew.cooper3@citrix.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Fri, Nov 25, 2016 at 07:04:51PM +0000, Andrew Cooper wrote: > As identified during review, using BUG_ON() before `lidt` will result in a > triple fault, even on APs. > > Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com> > --- > CC: Jan Beulich <JBeulich@suse.com> > CC: Wei Liu <wei.liu2@citrix.com> On the basis that this is a critical bug fix: Release-acked-by: Wei Liu <wei.liu2@citrix.com>
>>> On 25.11.16 at 20:04, <andrew.cooper3@citrix.com> wrote: > As identified during review, using BUG_ON() before `lidt` will result in a > triple fault, even on APs. Oh, I did commit v1 instead of v2, sorry. > Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com> Reviewed-by: Jan Beulich <jbeulich@suse.com>
>>> On 25.11.16 at 20:04, <andrew.cooper3@citrix.com> wrote: > @@ -672,6 +667,15 @@ void load_system_tables(void) > asm volatile ("lidt %0" : : "m" (idtr) ); > asm volatile ("ltr %w0" : : "rm" (TSS_ENTRY << 3) ); > asm volatile ("lldt %w0" : : "rm" (0) ); > + > + /* > + * Bottom-of-stack must be 16-byte aligned! > + * > + * Defer checks until exception support is sufficiently set up. > + */ I've applied this right away, correcting the indentation issue here. Jan
diff --git a/xen/arch/x86/cpu/common.c b/xen/arch/x86/cpu/common.c index 06ee401..16cf001 100644 --- a/xen/arch/x86/cpu/common.c +++ b/xen/arch/x86/cpu/common.c @@ -643,11 +643,6 @@ void load_system_tables(void) .limit = (IDT_ENTRIES * sizeof(idt_entry_t)) - 1, }; - /* Bottom-of-stack must be 16-byte aligned! */ - BUILD_BUG_ON((sizeof(struct cpu_info) - - offsetof(struct cpu_info, guest_cpu_user_regs.es)) & 0xf); - BUG_ON(system_state != SYS_STATE_early_boot && (stack_bottom & 0xf)); - /* Main stack for interrupts/exceptions. */ tss->rsp0 = stack_bottom; tss->bitmap = IOBMP_INVALID_OFFSET; @@ -672,6 +667,15 @@ void load_system_tables(void) asm volatile ("lidt %0" : : "m" (idtr) ); asm volatile ("ltr %w0" : : "rm" (TSS_ENTRY << 3) ); asm volatile ("lldt %w0" : : "rm" (0) ); + + /* + * Bottom-of-stack must be 16-byte aligned! + * + * Defer checks until exception support is sufficiently set up. + */ + BUILD_BUG_ON((sizeof(struct cpu_info) - + offsetof(struct cpu_info, guest_cpu_user_regs.es)) & 0xf); + BUG_ON(system_state != SYS_STATE_early_boot && (stack_bottom & 0xf)); } /*
As identified during review, using BUG_ON() before `lidt` will result in a triple fault, even on APs. Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com> --- CC: Jan Beulich <JBeulich@suse.com> CC: Wei Liu <wei.liu2@citrix.com> --- xen/arch/x86/cpu/common.c | 14 +++++++++----- 1 file changed, 9 insertions(+), 5 deletions(-)