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| author | Dominik Dingel <dingel@linux.vnet.ibm.com> | 2013-06-17 16:25:18 +0200 |
|---|---|---|
| committer | Christian Borntraeger <borntraeger@de.ibm.com> | 2014-01-30 12:50:39 +0100 |
| commit | 24eb3a824c4f3ccfaa2305dc1d9d9e2a708828c5 (patch) | |
| tree | a889cb48f43502fb8db57d40ef6f342382d638b6 /arch/s390/mm/fault.c | |
| parent | a91b8ebe8671980151e0a19ee9fec6b0e1ae1d58 (diff) | |
| download | op-kernel-dev-24eb3a824c4f3ccfaa2305dc1d9d9e2a708828c5.zip op-kernel-dev-24eb3a824c4f3ccfaa2305dc1d9d9e2a708828c5.tar.gz | |
KVM: s390: Add FAULT_FLAG_RETRY_NOWAIT for guest fault
In the case of a fault, we will retry to exit sie64 but with gmap fault
indication for this thread set. This makes it possible to handle async
page faults.
Based on a patch from Martin Schwidefsky.
Signed-off-by: Dominik Dingel <dingel@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Diffstat (limited to 'arch/s390/mm/fault.c')
| -rw-r--r-- | arch/s390/mm/fault.c | 26 |
1 files changed, 22 insertions, 4 deletions
diff --git a/arch/s390/mm/fault.c b/arch/s390/mm/fault.c index d95265b2..88cef50 100644 --- a/arch/s390/mm/fault.c +++ b/arch/s390/mm/fault.c @@ -50,6 +50,7 @@ #define VM_FAULT_BADMAP 0x020000 #define VM_FAULT_BADACCESS 0x040000 #define VM_FAULT_SIGNAL 0x080000 +#define VM_FAULT_PFAULT 0x100000 static unsigned long store_indication __read_mostly; @@ -227,6 +228,7 @@ static noinline void do_fault_error(struct pt_regs *regs, int fault) return; } case VM_FAULT_BADCONTEXT: + case VM_FAULT_PFAULT: do_no_context(regs); break; case VM_FAULT_SIGNAL: @@ -264,6 +266,9 @@ static noinline void do_fault_error(struct pt_regs *regs, int fault) */ static inline int do_exception(struct pt_regs *regs, int access) { +#ifdef CONFIG_PGSTE + struct gmap *gmap; +#endif struct task_struct *tsk; struct mm_struct *mm; struct vm_area_struct *vma; @@ -304,9 +309,10 @@ static inline int do_exception(struct pt_regs *regs, int access) down_read(&mm->mmap_sem); #ifdef CONFIG_PGSTE - if ((current->flags & PF_VCPU) && S390_lowcore.gmap) { - address = __gmap_fault(address, - (struct gmap *) S390_lowcore.gmap); + gmap = (struct gmap *) + ((current->flags & PF_VCPU) ? S390_lowcore.gmap : 0); + if (gmap) { + address = __gmap_fault(address, gmap); if (address == -EFAULT) { fault = VM_FAULT_BADMAP; goto out_up; @@ -315,6 +321,8 @@ static inline int do_exception(struct pt_regs *regs, int access) fault = VM_FAULT_OOM; goto out_up; } + if (gmap->pfault_enabled) + flags |= FAULT_FLAG_RETRY_NOWAIT; } #endif @@ -371,9 +379,19 @@ retry: regs, address); } if (fault & VM_FAULT_RETRY) { +#ifdef CONFIG_PGSTE + if (gmap && (flags & FAULT_FLAG_RETRY_NOWAIT)) { + /* FAULT_FLAG_RETRY_NOWAIT has been set, + * mmap_sem has not been released */ + current->thread.gmap_pfault = 1; + fault = VM_FAULT_PFAULT; + goto out_up; + } +#endif /* Clear FAULT_FLAG_ALLOW_RETRY to avoid any risk * of starvation. */ - flags &= ~FAULT_FLAG_ALLOW_RETRY; + flags &= ~(FAULT_FLAG_ALLOW_RETRY | + FAULT_FLAG_RETRY_NOWAIT); flags |= FAULT_FLAG_TRIED; down_read(&mm->mmap_sem); goto retry; |
