diff options
Diffstat (limited to 'arch/x86/mm/fault.c')
| -rw-r--r-- | arch/x86/mm/fault.c | 13 |
1 files changed, 8 insertions, 5 deletions
diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c index 42606a04ae85..82bf37a5c9ec 100644 --- a/arch/x86/mm/fault.c +++ b/arch/x86/mm/fault.c @@ -1446,11 +1446,14 @@ DEFINE_IDTENTRY_RAW_ERRORCODE(exc_page_fault) prefetchw(¤t->mm->mmap_lock); /* - * 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." + * KVM uses #PF vector to deliver 'page not present' events to guests + * (asynchronous page fault mechanism). The event happens when a + * userspace task is trying to access some valid (from guest's point of + * view) memory which is not currently mapped by the host (e.g. the + * memory is swapped out). Note, the corresponding "page ready" event + * which is injected when the memory becomes available, is delived via + * an interrupt mechanism and not a #PF exception + * (see arch/x86/kernel/kvm.c: sysvec_kvm_asyncpf_interrupt()). * * We are relying on the interrupted context being sane (valid RSP, * relevant locks not held, etc.), which is fine as long as the |