linux-kernel - [RFC PATCH 05/18] KVM: Add KVM_PFN_ERR

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Message-ID: <20240710234222.2333120-6-jthoughton@google.com>
Date: Wed, 10 Jul 2024 23:42:09 +0000
From: James Houghton <jthoughton@...gle.com>
To: Paolo Bonzini <pbonzini@...hat.com>
Cc: Marc Zyngier <maz@...nel.org>, Oliver Upton <oliver.upton@...ux.dev>, 
	James Morse <james.morse@....com>, Suzuki K Poulose <suzuki.poulose@....com>, 
	Zenghui Yu <yuzenghui@...wei.com>, Sean Christopherson <seanjc@...gle.com>, Shuah Khan <shuah@...nel.org>, 
	Peter Xu <peterx@...hat.org>, Axel Rasmussen <axelrasmussen@...gle.com>, 
	David Matlack <dmatlack@...gle.com>, James Houghton <jthoughton@...gle.com>, kvm@...r.kernel.org, 
	linux-doc@...r.kernel.org, linux-kernel@...r.kernel.org, 
	linux-arm-kernel@...ts.infradead.org, kvmarm@...ts.linux.dev
Subject: [RFC PATCH 05/18] KVM: Add KVM_PFN_ERR_USERFAULT

When a GFN -> HVA translation (__gfn_to_hva_many()) fails with
KVM_HVA_ERR_USERFAULT as part of a GFN -> PFN conversion
(__gfn_to_pfn_memslot()), we need to return some kind of KVM_PFN_ERR.

Introduce a new KVM_PFN_ERR_USERFAULT so that callers know that it is a
userfault.

Signed-off-by: James Houghton <jthoughton@...gle.com>
---
 include/linux/kvm_host.h | 1 +
 virt/kvm/kvm_main.c      | 8 +++++---
 2 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 4cca896fb44a..2005906c78c8 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -97,6 +97,7 @@
 #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)
+#define KVM_PFN_ERR_USERFAULT	(KVM_PFN_ERR_MASK + 4)
 
 /*
  * error pfns indicate that the gfn is in slot but faild to
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 758deb90a050..840e02c75fe3 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -3009,9 +3009,11 @@ kvm_pfn_t __gfn_to_pfn_memslot(const struct kvm_memory_slot *slot, gfn_t gfn,
 	if (kvm_is_error_hva(addr)) {
 		if (writable)
 			*writable = false;
-
-		return addr == KVM_HVA_ERR_RO_BAD ? KVM_PFN_ERR_RO_FAULT :
-						    KVM_PFN_NOSLOT;
+		if (addr == KVM_HVA_ERR_RO_BAD)
+			return KVM_PFN_ERR_RO_FAULT;
+		if (addr == KVM_HVA_ERR_USERFAULT)
+			return KVM_PFN_ERR_USERFAULT;
+		return KVM_PFN_NOSLOT;
 	}
 
 	/* Do not map writable pfn in the readonly memslot. */
-- 
2.45.2.993.g49e7a77208-goog