Enable x86 slow page faults to be able to respond to non-fatal signals,
returning -EINTR properly when it happens.
Signed-off-by: Peter Xu <peterx@xxxxxxxxxx>
---
arch/x86/kvm/mmu/mmu.c | 16 +++++++++++++---
1 file changed, 13 insertions(+), 3 deletions(-)
diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index cc26f425f41c..83b9c034313d 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -3148,8 +3148,13 @@ static void kvm_send_hwpoison_signal(unsigned long address, struct task_struct *
send_sig_mceerr(BUS_MCEERR_AR, (void __user *)address, PAGE_SHIFT, tsk);
}
-static int kvm_handle_bad_page(struct kvm_vcpu *vcpu, gfn_t gfn, kvm_pfn_t pfn)
+static int kvm_handle_error_pfn(struct kvm_vcpu *vcpu, gfn_t gfn, kvm_pfn_t pfn)
{
+ if (is_sigpending_pfn(pfn)) {
+ kvm_handle_signal_exit(vcpu);
+ return -EINTR;
+ }
+
/*
* Do not cache the mmio info caused by writing the readonly gfn
* into the spte otherwise read access on readonly gfn also can
@@ -3171,7 +3176,7 @@ static int handle_abnormal_pfn(struct kvm_vcpu *vcpu, struct kvm_page_fault *fau
{
/* The pfn is invalid, report the error! */
if (unlikely(is_error_pfn(fault->pfn)))
- return kvm_handle_bad_page(vcpu, fault->gfn, fault->pfn);
+ return kvm_handle_error_pfn(vcpu, fault->gfn, fault->pfn);
if (unlikely(!fault->slot)) {
gva_t gva = fault->is_tdp ? 0 : fault->addr;
@@ -4186,7 +4191,12 @@ static int kvm_faultin_pfn(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault)
}
}
- fault->pfn = __gfn_to_pfn_memslot(slot, fault->gfn, false, false, NULL,
+ /*
+ * Allow gup to bail on pending non-fatal signals when it's also allowed
+ * to wait for IO. Note, gup always bails if it is unable to quickly
+ * get a page and a fatal signal, i.e. SIGKILL, is pending.
+ */
+ fault->pfn = __gfn_to_pfn_memslot(slot, fault->gfn, false, true, NULL,
fault->write, &fault->map_writable,
&fault->hva);
return RET_PF_CONTINUE;
--
2.37.3
