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From: Steven Price <steven.price@arm.com>
To: Marc Zyngier <maz@kernel.org>, Will Deacon <will@kernel.org>,
	linux-arm-kernel@lists.infradead.org,
	kvmarm@lists.cs.columbia.edu
Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
	Catalin Marinas <catalin.marinas@arm.com>,
	linux-doc@vger.kernel.org, Russell King <linux@armlinux.org.uk>,
	Steven Price <steven.price@arm.com>,
	Paolo Bonzini <pbonzini@redhat.com>
Subject: [PATCH v6 04/10] KVM: Implement kvm_put_guest()
Date: Fri, 11 Oct 2019 13:59:24 +0100
Message-ID: <20191011125930.40834-5-steven.price@arm.com> (raw)
In-Reply-To: <20191011125930.40834-1-steven.price@arm.com>

kvm_put_guest() is analogous to put_user() - it writes a single value to
the guest physical address. The implementation is built upon put_user()
and so it has the same single copy atomic properties.

Signed-off-by: Steven Price <steven.price@arm.com>
---
 include/linux/kvm_host.h | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index fcb46b3374c6..bf0ae1825b9c 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -746,6 +746,28 @@ int kvm_write_guest_offset_cached(struct kvm *kvm, struct gfn_to_hva_cache *ghc,
 				  unsigned long len);
 int kvm_gfn_to_hva_cache_init(struct kvm *kvm, struct gfn_to_hva_cache *ghc,
 			      gpa_t gpa, unsigned long len);
+
+#define __kvm_put_guest(kvm, gfn, offset, value, type)			\
+({									\
+	unsigned long __addr = gfn_to_hva(kvm, gfn);			\
+	type __user *__uaddr = (type __user *)(__addr + offset);	\
+	int __ret = -EFAULT;						\
+									\
+	if (!kvm_is_error_hva(__addr))					\
+		__ret = put_user(value, __uaddr);			\
+	if (!__ret)							\
+		mark_page_dirty(kvm, gfn);				\
+	__ret;								\
+})
+
+#define kvm_put_guest(kvm, gpa, value, type)				\
+({									\
+	gpa_t __gpa = gpa;						\
+	struct kvm *__kvm = kvm;					\
+	__kvm_put_guest(__kvm, __gpa >> PAGE_SHIFT,			\
+			offset_in_page(__gpa), (value), type);		\
+})
+
 int kvm_clear_guest_page(struct kvm *kvm, gfn_t gfn, int offset, int len);
 int kvm_clear_guest(struct kvm *kvm, gpa_t gpa, unsigned long len);
 struct kvm_memory_slot *gfn_to_memslot(struct kvm *kvm, gfn_t gfn);
-- 
2.20.1

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  parent reply index

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-10-11 12:59 [PATCH v6 00/10] arm64: Stolen time support Steven Price
2019-10-11 12:59 ` [PATCH v6 01/10] KVM: arm64: Document PV-time interface Steven Price
2019-10-11 12:59 ` [PATCH v6 02/10] KVM: arm/arm64: Factor out hypercall handling from PSCI code Steven Price
2019-10-11 12:59 ` [PATCH v6 03/10] KVM: arm64: Implement PV_TIME_FEATURES call Steven Price
2019-10-11 12:59 ` Steven Price [this message]
2019-10-11 12:59 ` [PATCH v6 05/10] KVM: arm64: Support stolen time reporting via shared structure Steven Price
2019-10-19 11:12   ` Marc Zyngier
2019-10-11 12:59 ` [PATCH v6 06/10] KVM: Allow kvm_device_ops to be const Steven Price
2019-10-11 12:59 ` [PATCH v6 07/10] KVM: arm64: Provide VCPU attributes for stolen time Steven Price
2019-10-19 11:28   ` Marc Zyngier
2019-10-11 12:59 ` [PATCH v6 08/10] arm/arm64: Provide a wrapper for SMCCC 1.1 calls Steven Price
2019-10-11 12:59 ` [PATCH v6 09/10] arm/arm64: Make use of the SMCCC 1.1 wrapper Steven Price
2019-10-11 12:59 ` [PATCH v6 10/10] arm64: Retrieve stolen time as paravirtualized guest Steven Price
2019-10-19 20:28   ` Marc Zyngier

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