diff mbox series

[v4,4/4] kvm: x86: Allow to respond to generic signals during slow PF

Message ID 20221011195947.557281-1-peterx@redhat.com (mailing list archive)
State New
Headers show
Series kvm/mm: Allow GUP to respond to non fatal signals | expand

Commit Message

Peter Xu Oct. 11, 2022, 7:59 p.m. UTC 
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@redhat.com>
---
 arch/x86/kvm/mmu/mmu.c | 16 +++++++++++++---
 1 file changed, 13 insertions(+), 3 deletions(-)

Comments

Sean Christopherson Oct. 26, 2022, 10:51 p.m. UTC | #1 
"KVM: x86/mmu:" for the shortlog.

On Tue, Oct 11, 2022, Peter Xu wrote:
> Enable x86 slow page faults to be able to respond to non-fatal signals,
> returning -EINTR properly when it happens.

Probably worth adding:

  Opportunistically rename kvm_handle_bad_page() to kvm_handle_error_pfn()
  as an error pfn doesn't necessarily mean the page is "bad".

> Signed-off-by: Peter Xu <peterx@redhat.com>
> ---

Reviewed-by: Sean Christopherson <seanjc@google.com>
diff mbox series

Patch

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;