linux-kernel - [PATCH v4 2/4] kvm: Add KVM_PFN_ERR

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Message-Id: <20221011195809.557016-3-peterx@redhat.com>
Date:   Tue, 11 Oct 2022 15:58:07 -0400
From:   Peter Xu <peterx@...hat.com>
To:     kvm@...r.kernel.org, linux-kernel@...r.kernel.org
Cc:     Sean Christopherson <seanjc@...gle.com>, peterx@...hat.com,
        John Hubbard <jhubbard@...dia.com>,
        Paolo Bonzini <pbonzini@...hat.com>,
        David Matlack <dmatlack@...gle.com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Andrea Arcangeli <aarcange@...hat.com>,
        "Dr . David Alan Gilbert" <dgilbert@...hat.com>,
        David Hildenbrand <david@...hat.com>,
        Linux MM Mailing List <linux-mm@...ck.org>,
        Mike Kravetz <mike.kravetz@...cle.com>
Subject: [PATCH v4 2/4] kvm: Add KVM_PFN_ERR_SIGPENDING

Add a new pfn error to show that we've got a pending signal to handle
during hva_to_pfn_slow() procedure (of -EINTR retval).

Signed-off-by: Peter Xu <peterx@...hat.com>
---
 include/linux/kvm_host.h | 10 ++++++++++
 virt/kvm/kvm_main.c      |  2 ++
 2 files changed, 12 insertions(+)

diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 32f259fa5801..92baa930b891 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -96,6 +96,7 @@
 #define KVM_PFN_ERR_FAULT	(KVM_PFN_ERR_MASK)
 #define KVM_PFN_ERR_HWPOISON	(KVM_PFN_ERR_MASK + 1)
 #define KVM_PFN_ERR_RO_FAULT	(KVM_PFN_ERR_MASK + 2)
+#define KVM_PFN_ERR_SIGPENDING	(KVM_PFN_ERR_MASK + 3)
 
 /*
  * error pfns indicate that the gfn is in slot but faild to
@@ -106,6 +107,15 @@ static inline bool is_error_pfn(kvm_pfn_t pfn)
 	return !!(pfn & KVM_PFN_ERR_MASK);
 }
 
+/*
+ * KVM_PFN_ERR_SIGPENDING indicates that fetching the PFN was interrupted
+ * by a pending signal.  Note, the signal may or may not be fatal.
+ */
+static inline bool is_sigpending_pfn(kvm_pfn_t pfn)
+{
+	return pfn == KVM_PFN_ERR_SIGPENDING;
+}
+
 /*
  * error_noslot pfns indicate that the gfn can not be
  * translated to pfn - it is not in slot or failed to
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index e30f1b4ecfa5..e20a59dcda32 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -2667,6 +2667,8 @@ kvm_pfn_t hva_to_pfn(unsigned long addr, bool atomic, bool *async,
 	npages = hva_to_pfn_slow(addr, async, write_fault, writable, &pfn);
 	if (npages == 1)
 		return pfn;
+	if (npages == -EINTR)
+		return KVM_PFN_ERR_SIGPENDING;
 
 	mmap_read_lock(current->mm);
 	if (npages == -EHWPOISON ||
-- 
2.37.3