[PATCH v10 2/6] KVM: Add generic implementation of kvm_vm_ioctl_get_dirty_log

Mario Smarduch m.smarduch at samsung.com
Tue Aug 26 16:51:08 PDT 2014


Add support for generic implementation of dirty log read function. For now both
x86_64 and ARMv7 share generic dirty log read. Other architectures call
their architecture specific functions.

Signed-off-by: Mario Smarduch <m.smarduch at samsung.com>
---
 arch/arm/include/asm/kvm_host.h     |  2 +
 arch/arm/kvm/Kconfig                |  1 +
 arch/arm/kvm/arm.c                  |  2 +-
 arch/arm64/include/asm/kvm_host.h   |  2 +
 arch/arm64/kvm/Kconfig              |  1 +
 arch/ia64/include/asm/kvm_host.h    |  1 +
 arch/ia64/kvm/Kconfig               |  1 +
 arch/ia64/kvm/kvm-ia64.c            |  2 +-
 arch/mips/include/asm/kvm_host.h    |  1 +
 arch/mips/kvm/Kconfig               |  1 +
 arch/mips/kvm/mips.c                |  2 +-
 arch/powerpc/include/asm/kvm_host.h |  2 +
 arch/powerpc/kvm/Kconfig            |  1 +
 arch/powerpc/kvm/book3s.c           |  2 +-
 arch/powerpc/kvm/booke.c            |  2 +-
 arch/s390/include/asm/kvm_host.h    |  2 +
 arch/s390/kvm/Kconfig               |  1 +
 arch/s390/kvm/kvm-s390.c            |  2 +-
 arch/x86/kvm/x86.c                  | 86 -----------------------------------
 include/linux/kvm_host.h            |  2 +
 virt/kvm/Kconfig                    |  3 ++
 virt/kvm/kvm_main.c                 | 90 +++++++++++++++++++++++++++++++++++++
 22 files changed, 117 insertions(+), 92 deletions(-)

diff --git a/arch/arm/include/asm/kvm_host.h b/arch/arm/include/asm/kvm_host.h
index 193ceaf..8fc078d 100644
--- a/arch/arm/include/asm/kvm_host.h
+++ b/arch/arm/include/asm/kvm_host.h
@@ -231,4 +231,6 @@ int kvm_perf_teardown(void);
 u64 kvm_arm_timer_get_reg(struct kvm_vcpu *, u64 regid);
 int kvm_arm_timer_set_reg(struct kvm_vcpu *, u64 regid, u64 value);
 
+int kvm_arch_vm_ioctl_get_dirty_log(struct kvm *kvm, struct kvm_dirty_log *log);
+
 #endif /* __ARM_KVM_HOST_H__ */
diff --git a/arch/arm/kvm/Kconfig b/arch/arm/kvm/Kconfig
index 4be5bb1..cd9bb1c 100644
--- a/arch/arm/kvm/Kconfig
+++ b/arch/arm/kvm/Kconfig
@@ -23,6 +23,7 @@ config KVM
 	select HAVE_KVM_CPU_RELAX_INTERCEPT
 	select KVM_MMIO
 	select KVM_ARM_HOST
+	select HAVE_KVM_ARCH_DIRTY_LOG
 	depends on ARM_VIRT_EXT && ARM_LPAE && !CPU_BIG_ENDIAN
 	---help---
 	  Support hosting virtualized guest machines. You will also
diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c
index 3c82b37..c52b2bd 100644
--- a/arch/arm/kvm/arm.c
+++ b/arch/arm/kvm/arm.c
@@ -774,7 +774,7 @@ long kvm_arch_vcpu_ioctl(struct file *filp,
 	}
 }
 
-int kvm_vm_ioctl_get_dirty_log(struct kvm *kvm, struct kvm_dirty_log *log)
+int kvm_arch_vm_ioctl_get_dirty_log(struct kvm *kvm, struct kvm_dirty_log *log)
 {
 	return -EINVAL;
 }
diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index 92242ce..b4a280b 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -200,4 +200,6 @@ static inline void __cpu_init_hyp_mode(phys_addr_t boot_pgd_ptr,
 		     hyp_stack_ptr, vector_ptr);
 }
 
+int kvm_arch_vm_ioctl_get_dirty_log(struct kvm *kvm, struct kvm_dirty_log *log);
+
 #endif /* __ARM64_KVM_HOST_H__ */
diff --git a/arch/arm64/kvm/Kconfig b/arch/arm64/kvm/Kconfig
index 8ba85e9..40a8d19 100644
--- a/arch/arm64/kvm/Kconfig
+++ b/arch/arm64/kvm/Kconfig
@@ -26,6 +26,7 @@ config KVM
 	select KVM_ARM_HOST
 	select KVM_ARM_VGIC
 	select KVM_ARM_TIMER
+	select HAVE_KVM_ARCH_DIRTY_LOG
 	---help---
 	  Support hosting virtualized guest machines.
 
diff --git a/arch/ia64/include/asm/kvm_host.h b/arch/ia64/include/asm/kvm_host.h
index db95f57..d79f520 100644
--- a/arch/ia64/include/asm/kvm_host.h
+++ b/arch/ia64/include/asm/kvm_host.h
@@ -594,6 +594,7 @@ void kvm_sal_emul(struct kvm_vcpu *vcpu);
 #define __KVM_HAVE_ARCH_VM_ALLOC 1
 struct kvm *kvm_arch_alloc_vm(void);
 void kvm_arch_free_vm(struct kvm *kvm);
+int kvm_arch_vm_ioctl_get_dirty_log(struct kvm *kvm, struct kvm_dirty_log *log);
 
 #endif /* __ASSEMBLY__*/
 
diff --git a/arch/ia64/kvm/Kconfig b/arch/ia64/kvm/Kconfig
index 990b864..217f10a 100644
--- a/arch/ia64/kvm/Kconfig
+++ b/arch/ia64/kvm/Kconfig
@@ -28,6 +28,7 @@ config KVM
 	select HAVE_KVM_IRQ_ROUTING
 	select KVM_APIC_ARCHITECTURE
 	select KVM_MMIO
+	select HAVE_KVM_ARCH_DIRTY_LOG
 	---help---
 	  Support hosting fully virtualized guest machines using hardware
 	  virtualization extensions.  You will need a fairly recent
diff --git a/arch/ia64/kvm/kvm-ia64.c b/arch/ia64/kvm/kvm-ia64.c
index 6a4309b..3166df5 100644
--- a/arch/ia64/kvm/kvm-ia64.c
+++ b/arch/ia64/kvm/kvm-ia64.c
@@ -1812,7 +1812,7 @@ static void kvm_ia64_sync_dirty_log(struct kvm *kvm,
 	spin_unlock(&kvm->arch.dirty_log_lock);
 }
 
-int kvm_vm_ioctl_get_dirty_log(struct kvm *kvm,
+int kvm_arch_vm_ioctl_get_dirty_log(struct kvm *kvm,
 		struct kvm_dirty_log *log)
 {
 	int r;
diff --git a/arch/mips/include/asm/kvm_host.h b/arch/mips/include/asm/kvm_host.h
index 7a3fc67..e2cd1ea 100644
--- a/arch/mips/include/asm/kvm_host.h
+++ b/arch/mips/include/asm/kvm_host.h
@@ -767,5 +767,6 @@ extern int kvm_mips_trans_mtc0(uint32_t inst, uint32_t *opc,
 extern void kvm_mips_dump_stats(struct kvm_vcpu *vcpu);
 extern unsigned long kvm_mips_get_ramsize(struct kvm *kvm);
 
+int kvm_arch_vm_ioctl_get_dirty_log(struct kvm *kvm, struct kvm_dirty_log *log);
 
 #endif /* __MIPS_KVM_HOST_H__ */
diff --git a/arch/mips/kvm/Kconfig b/arch/mips/kvm/Kconfig
index 30e334e..b57f49e 100644
--- a/arch/mips/kvm/Kconfig
+++ b/arch/mips/kvm/Kconfig
@@ -20,6 +20,7 @@ config KVM
 	select PREEMPT_NOTIFIERS
 	select ANON_INODES
 	select KVM_MMIO
+	select HAVE_KVM_ARCH_DIRTY_LOG
 	---help---
 	  Support for hosting Guest kernels.
 	  Currently supported on MIPS32 processors.
diff --git a/arch/mips/kvm/mips.c b/arch/mips/kvm/mips.c
index d687c6e..885fdfe 100644
--- a/arch/mips/kvm/mips.c
+++ b/arch/mips/kvm/mips.c
@@ -791,7 +791,7 @@ out:
 }
 
 /* Get (and clear) the dirty memory log for a memory slot. */
-int kvm_vm_ioctl_get_dirty_log(struct kvm *kvm, struct kvm_dirty_log *log)
+int kvm_arch_vm_ioctl_get_dirty_log(struct kvm *kvm, struct kvm_dirty_log *log)
 {
 	struct kvm_memory_slot *memslot;
 	unsigned long ga, ga_end;
diff --git a/arch/powerpc/include/asm/kvm_host.h b/arch/powerpc/include/asm/kvm_host.h
index bb66d8b..df092d2 100644
--- a/arch/powerpc/include/asm/kvm_host.h
+++ b/arch/powerpc/include/asm/kvm_host.h
@@ -683,4 +683,6 @@ struct kvm_vcpu_arch {
 #define __KVM_HAVE_ARCH_WQP
 #define __KVM_HAVE_CREATE_DEVICE
 
+int kvm_arch_vm_ioctl_get_dirty_log(struct kvm *kvm, struct kvm_dirty_log *log);
+
 #endif /* __POWERPC_KVM_HOST_H__ */
diff --git a/arch/powerpc/kvm/Kconfig b/arch/powerpc/kvm/Kconfig
index d6a53b9..4f28a82 100644
--- a/arch/powerpc/kvm/Kconfig
+++ b/arch/powerpc/kvm/Kconfig
@@ -21,6 +21,7 @@ config KVM
 	select PREEMPT_NOTIFIERS
 	select ANON_INODES
 	select HAVE_KVM_EVENTFD
+	select HAVE_KVM_ARCH_DIRTY_LOG
 
 config KVM_BOOK3S_HANDLER
 	bool
diff --git a/arch/powerpc/kvm/book3s.c b/arch/powerpc/kvm/book3s.c
index c254c27..304faa1 100644
--- a/arch/powerpc/kvm/book3s.c
+++ b/arch/powerpc/kvm/book3s.c
@@ -815,7 +815,7 @@ int kvmppc_core_check_requests(struct kvm_vcpu *vcpu)
 	return vcpu->kvm->arch.kvm_ops->check_requests(vcpu);
 }
 
-int kvm_vm_ioctl_get_dirty_log(struct kvm *kvm, struct kvm_dirty_log *log)
+int kvm_arch_vm_ioctl_get_dirty_log(struct kvm *kvm, struct kvm_dirty_log *log)
 {
 	return kvm->arch.kvm_ops->get_dirty_log(kvm, log);
 }
diff --git a/arch/powerpc/kvm/booke.c b/arch/powerpc/kvm/booke.c
index ab62109..50dd33d 100644
--- a/arch/powerpc/kvm/booke.c
+++ b/arch/powerpc/kvm/booke.c
@@ -1624,7 +1624,7 @@ int kvm_arch_vcpu_ioctl_translate(struct kvm_vcpu *vcpu,
 	return r;
 }
 
-int kvm_vm_ioctl_get_dirty_log(struct kvm *kvm, struct kvm_dirty_log *log)
+int kvm_arch_vm_ioctl_get_dirty_log(struct kvm *kvm, struct kvm_dirty_log *log)
 {
 	return -ENOTSUPP;
 }
diff --git a/arch/s390/include/asm/kvm_host.h b/arch/s390/include/asm/kvm_host.h
index 4181d7b..2f54644 100644
--- a/arch/s390/include/asm/kvm_host.h
+++ b/arch/s390/include/asm/kvm_host.h
@@ -432,6 +432,7 @@ static inline bool kvm_is_error_hva(unsigned long addr)
 }
 
 #define ASYNC_PF_PER_VCPU	64
+struct kvm;
 struct kvm_vcpu;
 struct kvm_async_pf;
 struct kvm_arch_async_pf {
@@ -451,4 +452,5 @@ void kvm_arch_async_page_present(struct kvm_vcpu *vcpu,
 
 extern int sie64a(struct kvm_s390_sie_block *, u64 *);
 extern char sie_exit;
+int kvm_arch_vm_ioctl_get_dirty_log(struct kvm *kvm, struct kvm_dirty_log *log);
 #endif
diff --git a/arch/s390/kvm/Kconfig b/arch/s390/kvm/Kconfig
index 10d529a..6306bb6 100644
--- a/arch/s390/kvm/Kconfig
+++ b/arch/s390/kvm/Kconfig
@@ -27,6 +27,7 @@ config KVM
 	select KVM_ASYNC_PF_SYNC
 	select HAVE_KVM_IRQCHIP
 	select HAVE_KVM_IRQ_ROUTING
+	select HAVE_KVM_ARCH_DIRTY_LOG
 	---help---
 	  Support hosting paravirtualized guest machines using the SIE
 	  virtualization capability on the mainframe. This should work
diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index 2f3e14f..7712cf6 100644
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -208,7 +208,7 @@ static void kvm_s390_sync_dirty_log(struct kvm *kvm,
 /*
  * Get (and clear) the dirty memory log for a memory slot.
  */
-int kvm_vm_ioctl_get_dirty_log(struct kvm *kvm,
+int kvm_arch_vm_ioctl_get_dirty_log(struct kvm *kvm,
 			       struct kvm_dirty_log *log)
 {
 	int r;
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 5a8691b..652bd28 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -3577,92 +3577,6 @@ static int kvm_vm_ioctl_reinject(struct kvm *kvm,
 	return 0;
 }
 
-/**
- * kvm_vm_ioctl_get_dirty_log - get and clear the log of dirty pages in a slot
- * @kvm: kvm instance
- * @log: slot id and address to which we copy the log
- *
- * We need to keep it in mind that VCPU threads can write to the bitmap
- * concurrently.  So, to avoid losing data, we keep the following order for
- * each bit:
- *
- *   1. Take a snapshot of the bit and clear it if needed.
- *   2. Write protect the corresponding page.
- *   3. Flush TLB's if needed.
- *   4. Copy the snapshot to the userspace.
- *
- * Between 2 and 3, the guest may write to the page using the remaining TLB
- * entry.  This is not a problem because the page will be reported dirty at
- * step 4 using the snapshot taken before and step 3 ensures that successive
- * writes will be logged for the next call.
- */
-int kvm_vm_ioctl_get_dirty_log(struct kvm *kvm, struct kvm_dirty_log *log)
-{
-	int r;
-	struct kvm_memory_slot *memslot;
-	unsigned long n, i;
-	unsigned long *dirty_bitmap;
-	unsigned long *dirty_bitmap_buffer;
-	bool is_dirty = false;
-
-	mutex_lock(&kvm->slots_lock);
-
-	r = -EINVAL;
-	if (log->slot >= KVM_USER_MEM_SLOTS)
-		goto out;
-
-	memslot = id_to_memslot(kvm->memslots, log->slot);
-
-	dirty_bitmap = memslot->dirty_bitmap;
-	r = -ENOENT;
-	if (!dirty_bitmap)
-		goto out;
-
-	n = kvm_dirty_bitmap_bytes(memslot);
-
-	dirty_bitmap_buffer = dirty_bitmap + n / sizeof(long);
-	memset(dirty_bitmap_buffer, 0, n);
-
-	spin_lock(&kvm->mmu_lock);
-
-	for (i = 0; i < n / sizeof(long); i++) {
-		unsigned long mask;
-		gfn_t offset;
-
-		if (!dirty_bitmap[i])
-			continue;
-
-		is_dirty = true;
-
-		mask = xchg(&dirty_bitmap[i], 0);
-		dirty_bitmap_buffer[i] = mask;
-
-		offset = i * BITS_PER_LONG;
-		kvm_mmu_write_protect_pt_masked(kvm, memslot, offset, mask);
-	}
-
-	spin_unlock(&kvm->mmu_lock);
-
-	/* See the comments in kvm_mmu_slot_remove_write_access(). */
-	lockdep_assert_held(&kvm->slots_lock);
-
-	/*
-	 * All the TLBs can be flushed out of mmu lock, see the comments in
-	 * kvm_mmu_slot_remove_write_access().
-	 */
-	if (is_dirty)
-		kvm_flush_remote_tlbs(kvm);
-
-	r = -EFAULT;
-	if (copy_to_user(log->dirty_bitmap, dirty_bitmap_buffer, n))
-		goto out;
-
-	r = 0;
-out:
-	mutex_unlock(&kvm->slots_lock);
-	return r;
-}
-
 int kvm_vm_ioctl_irq_line(struct kvm *kvm, struct kvm_irq_level *irq_event,
 			bool line_status)
 {
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index ec4e3bd..9a3c734 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -608,6 +608,8 @@ int kvm_get_dirty_log(struct kvm *kvm,
 			struct kvm_dirty_log *log, int *is_dirty);
 int kvm_vm_ioctl_get_dirty_log(struct kvm *kvm,
 				struct kvm_dirty_log *log);
+void kvm_mmu_write_protect_pt_masked(struct kvm *kvm,
+	struct kvm_memory_slot *slot, gfn_t gfn_offset, unsigned long mask);
 
 int kvm_vm_ioctl_irq_line(struct kvm *kvm, struct kvm_irq_level *irq_level,
 			bool line_status);
diff --git a/virt/kvm/Kconfig b/virt/kvm/Kconfig
index f1efaa5..975733f 100644
--- a/virt/kvm/Kconfig
+++ b/virt/kvm/Kconfig
@@ -37,3 +37,6 @@ config KVM_VFIO
 
 config HAVE_KVM_ARCH_TLB_FLUSH_ALL
        bool
+
+config HAVE_KVM_ARCH_DIRTY_LOG
+       bool
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index d0a24f5..1c27344 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -442,6 +442,96 @@ static int kvm_init_mmu_notifier(struct kvm *kvm)
 
 #endif /* CONFIG_MMU_NOTIFIER && KVM_ARCH_WANT_MMU_NOTIFIER */
 
+/**
+ * kvm_vm_ioctl_get_dirty_log - get and clear the log of dirty pages in a slot
+ * @kvm: kvm instance
+ * @log: slot id and address to which we copy the log
+ *
+ * We need to keep it in mind that VCPU threads can write to the bitmap
+ * concurrently.  So, to avoid losing data, we keep the following order for
+ * each bit:
+ *
+ *   1. Take a snapshot of the bit and clear it if needed.
+ *   2. Write protect the corresponding page.
+ *   3. Flush TLB's if needed.
+ *   4. Copy the snapshot to the userspace.
+ *
+ * Between 2 and 3, the guest may write to the page using the remaining TLB
+ * entry.  This is not a problem because the page will be reported dirty at
+ * step 4 using the snapshot taken before and step 3 ensures that successive
+ * writes will be logged for the next call.
+ */
+int kvm_vm_ioctl_get_dirty_log(struct kvm *kvm, struct kvm_dirty_log *log)
+{
+#ifdef CONFIG_HAVE_KVM_ARCH_DIRTY_LOG
+	return kvm_arch_vm_ioctl_get_dirty_log(kvm, log);
+#else
+	int r;
+	struct kvm_memory_slot *memslot;
+	unsigned long n, i;
+	unsigned long *dirty_bitmap;
+	unsigned long *dirty_bitmap_buffer;
+	bool is_dirty = false;
+
+	mutex_lock(&kvm->slots_lock);
+
+	r = -EINVAL;
+	if (log->slot >= KVM_USER_MEM_SLOTS)
+		goto out;
+
+	memslot = id_to_memslot(kvm->memslots, log->slot);
+
+	dirty_bitmap = memslot->dirty_bitmap;
+	r = -ENOENT;
+	if (!dirty_bitmap)
+		goto out;
+
+	n = kvm_dirty_bitmap_bytes(memslot);
+
+	dirty_bitmap_buffer = dirty_bitmap + n / sizeof(long);
+	memset(dirty_bitmap_buffer, 0, n);
+
+	spin_lock(&kvm->mmu_lock);
+
+	for (i = 0; i < n / sizeof(long); i++) {
+		unsigned long mask;
+		gfn_t offset;
+
+		if (!dirty_bitmap[i])
+			continue;
+
+		is_dirty = true;
+
+		mask = xchg(&dirty_bitmap[i], 0);
+		dirty_bitmap_buffer[i] = mask;
+
+		offset = i * BITS_PER_LONG;
+		kvm_mmu_write_protect_pt_masked(kvm, memslot, offset, mask);
+	}
+
+	spin_unlock(&kvm->mmu_lock);
+
+	/* See the comments in kvm_mmu_slot_remove_write_access(). */
+	lockdep_assert_held(&kvm->slots_lock);
+
+	/*
+	 * All the TLBs can be flushed out of mmu lock, see the comments in
+	 * kvm_mmu_slot_remove_write_access().
+	 */
+	if (is_dirty)
+		kvm_flush_remote_tlbs(kvm);
+
+	r = -EFAULT;
+	if (copy_to_user(log->dirty_bitmap, dirty_bitmap_buffer, n))
+		goto out;
+
+	r = 0;
+out:
+	mutex_unlock(&kvm->slots_lock);
+	return r;
+#endif
+}
+
 static void kvm_init_memslots_id(struct kvm *kvm)
 {
 	int i;
-- 
1.8.3.2




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