[PATCH RFC 2/2] target/kvm: Add interfaces needed for log dirty

[Yifei Jiang]

Add two interfaces of log dirty for kvm_main.c, and detele the interface
kvm_vm_ioctl_get_dirty_log which is redundantly defined.

CONFIG_KVM_GENERIC_DIRTYLOG_READ_PROTECT is added in defconfig.

Signed-off-by: Yifei Jiang <jiangyifei at huawei.com>
Signed-off-by: Yipeng Yin <yinyipeng1 at huawei.com>
---
 arch/riscv/configs/defconfig |  1 +
 arch/riscv/kvm/Kconfig       |  1 +
 arch/riscv/kvm/mmu.c         | 43 ++++++++++++++++++++++++++++++++++++
 arch/riscv/kvm/vm.c          |  6 -----
 4 files changed, 45 insertions(+), 6 deletions(-)

diff --git a/arch/riscv/configs/defconfig b/arch/riscv/configs/defconfig
index d36e1000bbd3..857d799672c2 100644
--- a/arch/riscv/configs/defconfig
+++ b/arch/riscv/configs/defconfig
@@ -19,6 +19,7 @@ CONFIG_SOC_VIRT=y
 CONFIG_SMP=y
 CONFIG_VIRTUALIZATION=y
 CONFIG_KVM=y
+CONFIG_KVM_GENERIC_DIRTYLOG_READ_PROTECT=y
 CONFIG_HOTPLUG_CPU=y
 CONFIG_MODULES=y
 CONFIG_MODULE_UNLOAD=y
diff --git a/arch/riscv/kvm/Kconfig b/arch/riscv/kvm/Kconfig
index 2356dc52ebb3..91fcffc70e5d 100644
--- a/arch/riscv/kvm/Kconfig
+++ b/arch/riscv/kvm/Kconfig
@@ -26,6 +26,7 @@ config KVM
 	select KVM_MMIO
 	select HAVE_KVM_VCPU_ASYNC_IOCTL
 	select SRCU
+	select KVM_GENERIC_DIRTYLOG_READ_PROTECT
 	help
 	  Support hosting virtualized guest machines.
 
diff --git a/arch/riscv/kvm/mmu.c b/arch/riscv/kvm/mmu.c
index 88bce80ee983..df2a470c25e4 100644
--- a/arch/riscv/kvm/mmu.c
+++ b/arch/riscv/kvm/mmu.c
@@ -358,6 +358,43 @@ void stage2_wp_memory_region(struct kvm *kvm, int slot)
 	kvm_flush_remote_tlbs(kvm);
 }
 
+/**
+ * kvm_mmu_write_protect_pt_masked() - write protect dirty pages
+ * @kvm:    The KVM pointer
+ * @slot:   The memory slot associated with mask
+ * @gfn_offset: The gfn offset in memory slot
+ * @mask:   The mask of dirty pages at offset 'gfn_offset' in this memory
+ *      slot to be write protected
+ *
+ * Walks bits set in mask write protects the associated pte's. Caller must
+ * acquire kvm_mmu_lock.
+ */
+static void kvm_mmu_write_protect_pt_masked(struct kvm *kvm,
+        struct kvm_memory_slot *slot,
+        gfn_t gfn_offset, unsigned long mask)
+{
+    phys_addr_t base_gfn = slot->base_gfn + gfn_offset;
+    phys_addr_t start = (base_gfn +  __ffs(mask)) << PAGE_SHIFT;
+    phys_addr_t end = (base_gfn + __fls(mask) + 1) << PAGE_SHIFT;
+
+    stage2_wp_range(kvm, start, end);
+}
+
+/*
+ * kvm_arch_mmu_enable_log_dirty_pt_masked - enable dirty logging for selected
+ * dirty pages.
+ *
+ * It calls kvm_mmu_write_protect_pt_masked to write protect selected pages to
+ * enable dirty logging for them.
+ */
+void kvm_arch_mmu_enable_log_dirty_pt_masked(struct kvm *kvm,
+        struct kvm_memory_slot *slot,
+        gfn_t gfn_offset, unsigned long mask)
+{
+    kvm_mmu_write_protect_pt_masked(kvm, slot, gfn_offset, mask);
+}
+
+
 int stage2_ioremap(struct kvm *kvm, gpa_t gpa, phys_addr_t hpa,
 		   unsigned long size, bool writable)
 {
@@ -433,6 +470,12 @@ void kvm_arch_sync_dirty_log(struct kvm *kvm, struct kvm_memory_slot *memslot)
 {
 }
 
+void kvm_arch_flush_remote_tlbs_memslot(struct kvm *kvm,
+					struct kvm_memory_slot *memslot)
+{
+	kvm_flush_remote_tlbs(kvm);
+}
+
 void kvm_arch_free_memslot(struct kvm *kvm, struct kvm_memory_slot *free)
 {
 }
diff --git a/arch/riscv/kvm/vm.c b/arch/riscv/kvm/vm.c
index 4f2498198cb5..f7405676903b 100644
--- a/arch/riscv/kvm/vm.c
+++ b/arch/riscv/kvm/vm.c
@@ -12,12 +12,6 @@
 #include <linux/uaccess.h>
 #include <linux/kvm_host.h>
 
-int kvm_vm_ioctl_get_dirty_log(struct kvm *kvm, struct kvm_dirty_log *log)
-{
-	/* TODO: To be added later. */
-	return -ENOTSUPP;
-}
-
 int kvm_arch_init_vm(struct kvm *kvm, unsigned long type)
 {
 	int r;
-- 
2.19.1