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authorAndy Lutomirski <luto@kernel.org>2016-03-16 14:14:21 -0700
committerIngo Molnar <mingo@kernel.org>2016-03-17 09:49:26 +0100
commitb7a584598aea7ca73140cb87b40319944dd3393f (patch)
tree79f30be94b46b3bf08eb2ab82921973fef2c0064 /arch/x86/include/asm/xen
parentb08983015cdddca7e41c95f5054e2a8fb222a264 (diff)
x86/iopl/64: Properly context-switch IOPL on Xen PV
On Xen PV, regs->flags doesn't reliably reflect IOPL and the exit-to-userspace code doesn't change IOPL. We need to context switch it manually. I'm doing this without going through paravirt because this is specific to Xen PV. After the dust settles, we can merge this with the 32-bit code, tidy up the iopl syscall implementation, and remove the set_iopl pvop entirely. Fixes XSA-171. Reviewewd-by: Jan Beulich <JBeulich@suse.com> Signed-off-by: Andy Lutomirski <luto@kernel.org> Cc: Andrew Cooper <andrew.cooper3@citrix.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: David Vrabel <david.vrabel@citrix.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Jan Beulich <JBeulich@suse.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: stable@vger.kernel.org Link: http://lkml.kernel.org/r/693c3bd7aeb4d3c27c92c622b7d0f554a458173c.1458162709.git.luto@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/x86/include/asm/xen')
-rw-r--r--arch/x86/include/asm/xen/hypervisor.h2
1 files changed, 2 insertions, 0 deletions
diff --git a/arch/x86/include/asm/xen/hypervisor.h b/arch/x86/include/asm/xen/hypervisor.h
index 8b2d4bea9962..39171b3646bb 100644
--- a/arch/x86/include/asm/xen/hypervisor.h
+++ b/arch/x86/include/asm/xen/hypervisor.h
@@ -62,4 +62,6 @@ void xen_arch_register_cpu(int num);
void xen_arch_unregister_cpu(int num);
#endif
+extern void xen_set_iopl_mask(unsigned mask);
+
#endif /* _ASM_X86_XEN_HYPERVISOR_H */