Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm

[tomoyo/tomoyo-test1.git] / arch / x86 / mm / fault.c

diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
index dffe8e4..c5437f2 100644 (file)
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -30,6 +30,7 @@
 #include <asm/desc.h>                  /* store_idt(), ...             */
 #include <asm/cpu_entry_area.h>                /* exception stack              */
 #include <asm/pgtable_areas.h>         /* VMALLOC_START, ...           */
+#include <asm/kvm_para.h>              /* kvm_handle_async_pf          */
 
 #define CREATE_TRACE_POINTS
 #include <asm/trace/exceptions.h>
@@ -1359,6 +1360,24 @@ do_page_fault(struct pt_regs *regs, unsigned long hw_error_code,
                unsigned long address)
 {
        prefetchw(&current->mm->mmap_sem);
+       /*
+        * KVM has two types of events that are, logically, interrupts, but
+        * are unfortunately delivered using the #PF vector.  These events are
+        * "you just accessed valid memory, but the host doesn't have it right
+        * now, so I'll put you to sleep if you continue" and "that memory
+        * you tried to access earlier is available now."
+        *
+        * We are relying on the interrupted context being sane (valid RSP,
+        * relevant locks not held, etc.), which is fine as long as the
+        * interrupted context had IF=1.  We are also relying on the KVM
+        * async pf type field and CR2 being read consistently instead of
+        * getting values from real and async page faults mixed up.
+        *
+        * Fingers crossed.
+        */
+       if (kvm_handle_async_pf(regs, (u32)address))
+               return;
+
        trace_page_fault_entries(regs, hw_error_code, address);
 
        if (unlikely(kmmio_fault(regs, address)))