[PATCH 07/11] KVM: add vcpu-specific functions to read/write/translate GFNs

From: Paolo Bonzini <pbonzini@redhat.com>
To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org
Cc: Xiao Guangrong <guangrong.xiao@linux.intel.com>,
	rkrcmar@redhat.com, bdas@redhat.com
Subject: [PATCH 07/11] KVM: add vcpu-specific functions to read/write/translate GFNs
Date: Mon, 18 May 2015 15:48:39 +0200	[thread overview]
Message-ID: <1431956923-35602-8-git-send-email-pbonzini@redhat.com> (raw)
In-Reply-To: <1431956923-35602-1-git-send-email-pbonzini@redhat.com>

We need to hide SMRAM from guests not running in SMM.  Therefore, all uses
of kvm_read_guest* and kvm_write_guest* must be changed to use different
address spaces depending on whether the VCPU is in system management mode.
We need to introduce a new family of functions for this.

For now, the functions are the same as the existing per-VM ones, except
for the type of the first argument, but later they will be changed to
use one of many "struct kvm_memslots" stored in struct kvm.

Whenever possible, slot-based functions are introduced, with two wrappers
for generic and vcpu-based actions.  kvm_read_guest and kvm_write_guest
are copied into kvm_vcpu_read_guest and kvm_vcpu_write_guest.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 include/linux/kvm_host.h |  19 +++++++
 virt/kvm/kvm_main.c      | 129 ++++++++++++++++++++++++++++++++++++++++++-----
 2 files changed, 135 insertions(+), 13 deletions(-)

diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index f35fd89c7919..427a1034a70e 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -471,6 +471,11 @@ static inline struct kvm_memslots *kvm_memslots(struct kvm *kvm)
 			|| lockdep_is_held(&kvm->slots_lock));
 }
 
+static inline struct kvm_memslots *kvm_vcpu_memslots(struct kvm_vcpu *vcpu)
+{
+	return kvm_memslots(vcpu->kvm);
+}
+
 static inline struct kvm_memory_slot *
 id_to_memslot(struct kvm_memslots *slots, int id)
 {
@@ -577,6 +582,20 @@ unsigned long kvm_host_page_size(struct kvm *kvm, gfn_t gfn);
 void mark_page_dirty(struct kvm *kvm, gfn_t gfn);
 void mark_page_dirty_in_slot(struct kvm_memory_slot *memslot, gfn_t gfn);
 
+struct kvm_memslots *kvm_vcpu_memslots(struct kvm_vcpu *vcpu);
+struct kvm_memory_slot *kvm_vcpu_gfn_to_memslot(struct kvm_vcpu *vcpu, gfn_t gfn);
+unsigned long kvm_vcpu_gfn_to_hva(struct kvm_vcpu *vcpu, gfn_t gfn);
+int kvm_vcpu_read_guest_page(struct kvm_vcpu *vcpu, gfn_t gfn, void *data, int offset,
+			     int len);
+int kvm_vcpu_read_guest_atomic(struct kvm_vcpu *vcpu, gpa_t gpa, void *data,
+			       unsigned long len);
+int kvm_vcpu_read_guest(struct kvm_vcpu *vcpu, gpa_t gpa, void *data,
+			unsigned long len);
+int kvm_vcpu_write_guest_page(struct kvm_vcpu *vcpu, gfn_t gfn, const void *data,
+			      int offset, int len);
+int kvm_vcpu_write_guest(struct kvm_vcpu *vcpu, gpa_t gpa, const void *data,
+			 unsigned long len);
+
 void kvm_vcpu_block(struct kvm_vcpu *vcpu);
 void kvm_vcpu_kick(struct kvm_vcpu *vcpu);
 int kvm_vcpu_yield_to(struct kvm_vcpu *target);
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 2818fca43732..2cbda443880b 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -1100,6 +1100,11 @@ struct kvm_memory_slot *gfn_to_memslot(struct kvm *kvm, gfn_t gfn)
 }
 EXPORT_SYMBOL_GPL(gfn_to_memslot);
 
+struct kvm_memory_slot *kvm_vcpu_gfn_to_memslot(struct kvm_vcpu *vcpu, gfn_t gfn)
+{
+	return __gfn_to_memslot(kvm_vcpu_memslots(vcpu), gfn);
+}
+
 int kvm_is_visible_gfn(struct kvm *kvm, gfn_t gfn)
 {
 	struct kvm_memory_slot *memslot = gfn_to_memslot(kvm, gfn);
@@ -1175,6 +1180,12 @@ unsigned long gfn_to_hva(struct kvm *kvm, gfn_t gfn)
 }
 EXPORT_SYMBOL_GPL(gfn_to_hva);
 
+unsigned long kvm_vcpu_gfn_to_hva(struct kvm_vcpu *vcpu, gfn_t gfn)
+{
+	return gfn_to_hva_many(kvm_vcpu_gfn_to_memslot(vcpu, gfn), gfn, NULL);
+}
+EXPORT_SYMBOL_GPL(kvm_vcpu_gfn_to_hva);
+
 /*
  * If writable is set to false, the hva returned by this function is only
  * allowed to be read.
@@ -1529,13 +1540,13 @@ static int next_segment(unsigned long len, int offset)
 		return len;
 }
 
-int kvm_read_guest_page(struct kvm *kvm, gfn_t gfn, void *data, int offset,
-			int len)
+static int __kvm_read_guest_page(struct kvm_memory_slot *slot, gfn_t gfn,
+				 void *data, int offset, int len)
 {
 	int r;
 	unsigned long addr;
 
-	addr = gfn_to_hva_prot(kvm, gfn, NULL);
+	addr = gfn_to_hva_memslot_prot(slot, gfn, NULL);
 	if (kvm_is_error_hva(addr))
 		return -EFAULT;
 	r = __copy_from_user(data, (void __user *)addr + offset, len);
@@ -1543,8 +1554,25 @@ int kvm_read_guest_page(struct kvm *kvm, gfn_t gfn, void *data, int offset,
 		return -EFAULT;
 	return 0;
 }
+
+int kvm_read_guest_page(struct kvm *kvm, gfn_t gfn, void *data, int offset,
+			int len)
+{
+	struct kvm_memory_slot *slot = gfn_to_memslot(kvm, gfn);
+
+	return __kvm_read_guest_page(slot, gfn, data, offset, len);
+}
 EXPORT_SYMBOL_GPL(kvm_read_guest_page);
 
+int kvm_vcpu_read_guest_page(struct kvm_vcpu *vcpu, gfn_t gfn, void *data,
+			     int offset, int len)
+{
+	struct kvm_memory_slot *slot = kvm_vcpu_gfn_to_memslot(vcpu, gfn);
+
+	return __kvm_read_guest_page(slot, gfn, data, offset, len);
+}
+EXPORT_SYMBOL_GPL(kvm_vcpu_read_guest_page);
+
 int kvm_read_guest(struct kvm *kvm, gpa_t gpa, void *data, unsigned long len)
 {
 	gfn_t gfn = gpa >> PAGE_SHIFT;
@@ -1565,15 +1593,33 @@ int kvm_read_guest(struct kvm *kvm, gpa_t gpa, void *data, unsigned long len)
 }
 EXPORT_SYMBOL_GPL(kvm_read_guest);
 
-int kvm_read_guest_atomic(struct kvm *kvm, gpa_t gpa, void *data,
-			  unsigned long len)
+int kvm_vcpu_read_guest(struct kvm_vcpu *vcpu, gpa_t gpa, void *data, unsigned long len)
 {
-	int r;
-	unsigned long addr;
 	gfn_t gfn = gpa >> PAGE_SHIFT;
+	int seg;
 	int offset = offset_in_page(gpa);
+	int ret;
 
-	addr = gfn_to_hva_prot(kvm, gfn, NULL);
+	while ((seg = next_segment(len, offset)) != 0) {
+		ret = kvm_vcpu_read_guest_page(vcpu, gfn, data, offset, seg);
+		if (ret < 0)
+			return ret;
+		offset = 0;
+		len -= seg;
+		data += seg;
+		++gfn;
+	}
+	return 0;
+}
+EXPORT_SYMBOL_GPL(kvm_vcpu_read_guest);
+
+static int __kvm_read_guest_atomic(struct kvm_memory_slot *slot, gfn_t gfn,
+			           void *data, int offset, unsigned long len)
+{
+	int r;
+	unsigned long addr;
+
+	addr = gfn_to_hva_memslot_prot(slot, gfn, NULL);
 	if (kvm_is_error_hva(addr))
 		return -EFAULT;
 	pagefault_disable();
@@ -1583,16 +1629,35 @@ int kvm_read_guest_atomic(struct kvm *kvm, gpa_t gpa, void *data,
 		return -EFAULT;
 	return 0;
 }
-EXPORT_SYMBOL(kvm_read_guest_atomic);
 
-int kvm_write_guest_page(struct kvm *kvm, gfn_t gfn, const void *data,
-			 int offset, int len)
+int kvm_read_guest_atomic(struct kvm *kvm, gpa_t gpa, void *data,
+			  unsigned long len)
+{
+	gfn_t gfn = gpa >> PAGE_SHIFT;
+	struct kvm_memory_slot *slot = gfn_to_memslot(kvm, gfn);
+	int offset = offset_in_page(gpa);
+
+	return __kvm_read_guest_atomic(slot, gpa, data, offset, len);
+}
+EXPORT_SYMBOL_GPL(kvm_read_guest_atomic);
+
+int kvm_vcpu_read_guest_atomic(struct kvm_vcpu *vcpu, gpa_t gpa,
+			       void *data, unsigned long len)
+{
+	gfn_t gfn = gpa >> PAGE_SHIFT;
+	struct kvm_memory_slot *slot = kvm_vcpu_gfn_to_memslot(vcpu, gfn);
+	int offset = offset_in_page(gpa);
+
+	return __kvm_read_guest_atomic(slot, gpa, data, offset, len);
+}
+EXPORT_SYMBOL_GPL(kvm_vcpu_read_guest_atomic);
+
+static int __kvm_write_guest_page(struct kvm_memory_slot *memslot, gfn_t gfn,
+			          const void *data, int offset, int len)
 {
 	int r;
-	struct kvm_memory_slot *memslot;
 	unsigned long addr;
 
-	memslot = gfn_to_memslot(kvm, gfn);
 	addr = gfn_to_hva_memslot(memslot, gfn);
 	if (kvm_is_error_hva(addr))
 		return -EFAULT;
@@ -1602,8 +1667,25 @@ int kvm_write_guest_page(struct kvm *kvm, gfn_t gfn, const void *data,
 	mark_page_dirty_in_slot(memslot, gfn);
 	return 0;
 }
+
+int kvm_write_guest_page(struct kvm *kvm, gfn_t gfn,
+			 const void *data, int offset, int len)
+{
+	struct kvm_memory_slot *slot = gfn_to_memslot(kvm, gfn);
+
+	return __kvm_write_guest_page(slot, gfn, data, offset, len);
+}
 EXPORT_SYMBOL_GPL(kvm_write_guest_page);
 
+int kvm_vcpu_write_guest_page(struct kvm_vcpu *vcpu, gfn_t gfn,
+			      const void *data, int offset, int len)
+{
+	struct kvm_memory_slot *slot = kvm_vcpu_gfn_to_memslot(vcpu, gfn);
+
+	return __kvm_write_guest_page(slot, gfn, data, offset, len);
+}
+EXPORT_SYMBOL_GPL(kvm_vcpu_write_guest_page);
+
 int kvm_write_guest(struct kvm *kvm, gpa_t gpa, const void *data,
 		    unsigned long len)
 {
@@ -1625,6 +1707,27 @@ int kvm_write_guest(struct kvm *kvm, gpa_t gpa, const void *data,
 }
 EXPORT_SYMBOL_GPL(kvm_write_guest);
 
+int kvm_vcpu_write_guest(struct kvm_vcpu *vcpu, gpa_t gpa, const void *data,
+		         unsigned long len)
+{
+	gfn_t gfn = gpa >> PAGE_SHIFT;
+	int seg;
+	int offset = offset_in_page(gpa);
+	int ret;
+
+	while ((seg = next_segment(len, offset)) != 0) {
+		ret = kvm_vcpu_write_guest_page(vcpu, gfn, data, offset, seg);
+		if (ret < 0)
+			return ret;
+		offset = 0;
+		len -= seg;
+		data += seg;
+		++gfn;
+	}
+	return 0;
+}
+EXPORT_SYMBOL_GPL(kvm_vcpu_write_guest);
+
 int kvm_gfn_to_hva_cache_init(struct kvm *kvm, struct gfn_to_hva_cache *ghc,
 			      gpa_t gpa, unsigned long len)
 {
-- 
1.8.3.1


