[PATCH v3 3/3] kvm/x86: Allow to respond to generic signals during slow page faults

From: Peter Xu
Date: Tue Aug 16 2022 - 20:36:30 EST


Enable x86 slow page faults to be able to respond to non-fatal signals.

Signed-off-by: Peter Xu <peterx@xxxxxxxxxx>
---
arch/x86/kvm/mmu/mmu.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index 23dc46da2f18..4a7d387a762a 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -4177,7 +4177,12 @@ 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;
--
2.32.0