From a6d5101661c88d642b1fc85657fb0c58da821aa7 Mon Sep 17 00:00:00 2001 From: Mario Smarduch Date: Thu, 15 Jan 2015 15:58:52 -0800 Subject: KVM: Add architecture-defined TLB flush support Allow architectures to override the generic kvm_flush_remote_tlbs() function via HAVE_KVM_ARCH_TLB_FLUSH_ALL. ARMv7 will need this to provide its own TLB flush interface. Reviewed-by: Christoffer Dall Reviewed-by: Marc Zyngier Reviewed-by: Paolo Bonzini Signed-off-by: Mario Smarduch --- virt/kvm/Kconfig | 3 +++ 1 file changed, 3 insertions(+) (limited to 'virt/kvm/Kconfig') diff --git a/virt/kvm/Kconfig b/virt/kvm/Kconfig index fc0c5e603eb4..3796a2132a06 100644 --- a/virt/kvm/Kconfig +++ b/virt/kvm/Kconfig @@ -37,3 +37,6 @@ config HAVE_KVM_CPU_RELAX_INTERCEPT config KVM_VFIO bool + +config HAVE_KVM_ARCH_TLB_FLUSH_ALL + bool -- cgit v1.2.3 From ba0513b5b8ffbcb0cc89e2f172c0bcb70497ba2e Mon Sep 17 00:00:00 2001 From: Mario Smarduch Date: Thu, 15 Jan 2015 15:58:53 -0800 Subject: KVM: Add generic support for dirty page logging kvm_get_dirty_log() provides generic handling of dirty bitmap, currently reused by several architectures. Building on that we intrdoduce kvm_get_dirty_log_protect() adding write protection to mark these pages dirty for future write access, before next KVM_GET_DIRTY_LOG ioctl call from user space. Reviewed-by: Christoffer Dall Signed-off-by: Mario Smarduch --- include/linux/kvm_host.h | 9 ++++++ virt/kvm/Kconfig | 6 ++++ virt/kvm/kvm_main.c | 80 ++++++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 95 insertions(+) (limited to 'virt/kvm/Kconfig') diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index 26f106022c88..3b934cc94cc8 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -611,6 +611,15 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext); int kvm_get_dirty_log(struct kvm *kvm, struct kvm_dirty_log *log, int *is_dirty); + +int kvm_get_dirty_log_protect(struct kvm *kvm, + struct kvm_dirty_log *log, bool *is_dirty); + +void kvm_arch_mmu_write_protect_pt_masked(struct kvm *kvm, + struct kvm_memory_slot *slot, + gfn_t gfn_offset, + unsigned long mask); + int kvm_vm_ioctl_get_dirty_log(struct kvm *kvm, struct kvm_dirty_log *log); diff --git a/virt/kvm/Kconfig b/virt/kvm/Kconfig index 3796a2132a06..314950c51d9f 100644 --- a/virt/kvm/Kconfig +++ b/virt/kvm/Kconfig @@ -40,3 +40,9 @@ config KVM_VFIO config HAVE_KVM_ARCH_TLB_FLUSH_ALL bool + +config HAVE_KVM_ARCH_DIRTY_LOG_PROTECT + bool + +config KVM_GENERIC_DIRTYLOG_READ_PROTECT + bool diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index d03bd2255801..246cf291c6fd 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -995,6 +995,86 @@ out: } EXPORT_SYMBOL_GPL(kvm_get_dirty_log); +#ifdef CONFIG_KVM_GENERIC_DIRTYLOG_READ_PROTECT +/** + * kvm_get_dirty_log_protect - get a snapshot of dirty pages, and if any pages + * are dirty write protect them for next write. + * @kvm: pointer to kvm instance + * @log: slot id and address to which we copy the log + * @is_dirty: flag set if any page is dirty + * + * We need to keep it in mind that VCPU threads can write to the bitmap + * concurrently. So, to avoid losing track of dirty pages we keep the + * following order: + * + * 1. Take a snapshot of the bit and clear it if needed. + * 2. Write protect the corresponding page. + * 3. Copy the snapshot to the userspace. + * 4. Upon return caller flushes TLB's if needed. + * + * Between 2 and 4, the guest may write to the page using the remaining TLB + * entry. This is not a problem because the page is reported dirty using + * the snapshot taken before and step 4 ensures that writes done after + * exiting to userspace will be logged for the next call. + * + */ +int kvm_get_dirty_log_protect(struct kvm *kvm, + struct kvm_dirty_log *log, bool *is_dirty) +{ + struct kvm_memory_slot *memslot; + int r, i; + unsigned long n; + unsigned long *dirty_bitmap; + unsigned long *dirty_bitmap_buffer; + + 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); + *is_dirty = false; + 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_arch_mmu_write_protect_pt_masked(kvm, memslot, offset, + mask); + } + + spin_unlock(&kvm->mmu_lock); + + r = -EFAULT; + if (copy_to_user(log->dirty_bitmap, dirty_bitmap_buffer, n)) + goto out; + + r = 0; +out: + return r; +} +EXPORT_SYMBOL_GPL(kvm_get_dirty_log_protect); +#endif + bool kvm_largepages_enabled(void) { return largepages_enabled; -- cgit v1.2.3 From 4b990589952f0e30aa860184ac6c76219a74632e Mon Sep 17 00:00:00 2001 From: Christoffer Dall Date: Fri, 23 Jan 2015 10:50:23 +0100 Subject: KVM: Remove unused config symbol The dirty patch logging series introduced both HAVE_KVM_ARCH_DIRTY_LOG_PROTECT and KVM_GENERIC_DIRTYLOG_READ_PROTECT config symbols, but only KVM_GENERIC_DIRTYLOG_READ_PROTECT is used. Just remove the unused one. (The config symbol was renamed during the development of the patch series and the old name just creeped in by accident.() Reported-by: Paul Bolle Signed-off-by: Christoffer Dall --- virt/kvm/Kconfig | 3 --- 1 file changed, 3 deletions(-) (limited to 'virt/kvm/Kconfig') diff --git a/virt/kvm/Kconfig b/virt/kvm/Kconfig index 314950c51d9f..50d110654b42 100644 --- a/virt/kvm/Kconfig +++ b/virt/kvm/Kconfig @@ -41,8 +41,5 @@ config KVM_VFIO config HAVE_KVM_ARCH_TLB_FLUSH_ALL bool -config HAVE_KVM_ARCH_DIRTY_LOG_PROTECT - bool - config KVM_GENERIC_DIRTYLOG_READ_PROTECT bool -- cgit v1.2.3 From de8e5d744051568c8aad35c1c2dcf8fd137d10c9 Mon Sep 17 00:00:00 2001 From: Christian Borntraeger Date: Tue, 3 Feb 2015 09:35:15 +0100 Subject: KVM: Disable compat ioctl for s390 We never had a 31bit QEMU/kuli running. We would need to review several ioctls to check if this creates holes, bugs or whatever to make it work. Lets just disable compat support for KVM on s390. Signed-off-by: Christian Borntraeger Acked-by: Paolo Bonzini --- virt/kvm/Kconfig | 4 ++++ virt/kvm/kvm_main.c | 12 ++++++------ 2 files changed, 10 insertions(+), 6 deletions(-) (limited to 'virt/kvm/Kconfig') diff --git a/virt/kvm/Kconfig b/virt/kvm/Kconfig index 50d110654b42..e2c876d5a03b 100644 --- a/virt/kvm/Kconfig +++ b/virt/kvm/Kconfig @@ -43,3 +43,7 @@ config HAVE_KVM_ARCH_TLB_FLUSH_ALL config KVM_GENERIC_DIRTYLOG_READ_PROTECT bool + +config KVM_COMPAT + def_bool y + depends on COMPAT && !S390 diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 32449e0e9aa8..8579f1876e5a 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -92,7 +92,7 @@ struct dentry *kvm_debugfs_dir; static long kvm_vcpu_ioctl(struct file *file, unsigned int ioctl, unsigned long arg); -#ifdef CONFIG_COMPAT +#ifdef CONFIG_KVM_COMPAT static long kvm_vcpu_compat_ioctl(struct file *file, unsigned int ioctl, unsigned long arg); #endif @@ -2052,7 +2052,7 @@ static int kvm_vcpu_release(struct inode *inode, struct file *filp) static struct file_operations kvm_vcpu_fops = { .release = kvm_vcpu_release, .unlocked_ioctl = kvm_vcpu_ioctl, -#ifdef CONFIG_COMPAT +#ifdef CONFIG_KVM_COMPAT .compat_ioctl = kvm_vcpu_compat_ioctl, #endif .mmap = kvm_vcpu_mmap, @@ -2342,7 +2342,7 @@ out: return r; } -#ifdef CONFIG_COMPAT +#ifdef CONFIG_KVM_COMPAT static long kvm_vcpu_compat_ioctl(struct file *filp, unsigned int ioctl, unsigned long arg) { @@ -2434,7 +2434,7 @@ static int kvm_device_release(struct inode *inode, struct file *filp) static const struct file_operations kvm_device_fops = { .unlocked_ioctl = kvm_device_ioctl, -#ifdef CONFIG_COMPAT +#ifdef CONFIG_KVM_COMPAT .compat_ioctl = kvm_device_ioctl, #endif .release = kvm_device_release, @@ -2721,7 +2721,7 @@ out: return r; } -#ifdef CONFIG_COMPAT +#ifdef CONFIG_KVM_COMPAT struct compat_kvm_dirty_log { __u32 slot; __u32 padding1; @@ -2768,7 +2768,7 @@ out: static struct file_operations kvm_vm_fops = { .release = kvm_vm_release, .unlocked_ioctl = kvm_vm_ioctl, -#ifdef CONFIG_COMPAT +#ifdef CONFIG_KVM_COMPAT .compat_ioctl = kvm_vm_compat_ioctl, #endif .llseek = noop_llseek, -- cgit v1.2.3