From e5d83c74a5800c2a1fa3ba982c1c4b2b39ae6db2 Mon Sep 17 00:00:00 2001 From: Paolo Bonzini Date: Thu, 16 Feb 2017 10:40:56 +0100 Subject: kvm: make KVM_CAP_ENABLE_CAP_VM architecture agnostic The first such capability to be handled in virt/kvm/ will be manual dirty page reprotection. Signed-off-by: Paolo Bonzini --- include/linux/kvm_host.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'include/linux') diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index c926698040e0..54cc06dd7e6c 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -765,6 +765,8 @@ int kvm_vm_ioctl_get_dirty_log(struct kvm *kvm, int kvm_vm_ioctl_irq_line(struct kvm *kvm, struct kvm_irq_level *irq_level, bool line_status); +int kvm_vm_ioctl_enable_cap(struct kvm *kvm, + struct kvm_enable_cap *cap); long kvm_arch_vm_ioctl(struct file *filp, unsigned int ioctl, unsigned long arg); -- cgit v1.2.3 From 8fe65a8299f9e1f40cb95308ab7b3c4ad80bf801 Mon Sep 17 00:00:00 2001 From: Paolo Bonzini Date: Tue, 23 Oct 2018 02:18:42 +0200 Subject: kvm: rename last argument to kvm_get_dirty_log_protect When manual dirty log reprotect will be enabled, kvm_get_dirty_log_protect's pointer argument will always be false on exit, because no TLB flush is needed until the manual re-protection operation. Rename it from "is_dirty" to "flush", which more accurately tells the caller what they have to do with it. Signed-off-by: Paolo Bonzini --- include/linux/kvm_host.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'include/linux') diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index 54cc06dd7e6c..8c56b2873b13 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -753,7 +753,7 @@ 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); + struct kvm_dirty_log *log, bool *flush); void kvm_arch_mmu_enable_log_dirty_pt_masked(struct kvm *kvm, struct kvm_memory_slot *slot, -- cgit v1.2.3 From 2a31b9db153530df4aa02dac8c32837bf5f47019 Mon Sep 17 00:00:00 2001 From: Paolo Bonzini Date: Tue, 23 Oct 2018 02:36:47 +0200 Subject: kvm: introduce manual dirty log reprotect There are two problems with KVM_GET_DIRTY_LOG. First, and less important, it can take kvm->mmu_lock for an extended period of time. Second, its user can actually see many false positives in some cases. The latter is due to a benign race like this: 1. KVM_GET_DIRTY_LOG returns a set of dirty pages and write protects them. 2. The guest modifies the pages, causing them to be marked ditry. 3. Userspace actually copies the pages. 4. KVM_GET_DIRTY_LOG returns those pages as dirty again, even though they were not written to since (3). This is especially a problem for large guests, where the time between (1) and (3) can be substantial. This patch introduces a new capability which, when enabled, makes KVM_GET_DIRTY_LOG not write-protect the pages it returns. Instead, userspace has to explicitly clear the dirty log bits just before using the content of the page. The new KVM_CLEAR_DIRTY_LOG ioctl can also operate on a 64-page granularity rather than requiring to sync a full memslot; this way, the mmu_lock is taken for small amounts of time, and only a small amount of time will pass between write protection of pages and the sending of their content. Signed-off-by: Paolo Bonzini --- include/linux/kvm_host.h | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'include/linux') diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index 8c56b2873b13..e065aeaae29e 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -449,6 +449,7 @@ struct kvm { #endif long tlbs_dirty; struct list_head devices; + bool manual_dirty_log_protect; struct dentry *debugfs_dentry; struct kvm_stat_data **debugfs_stat_data; struct srcu_struct srcu; @@ -754,6 +755,8 @@ int kvm_get_dirty_log(struct kvm *kvm, int kvm_get_dirty_log_protect(struct kvm *kvm, struct kvm_dirty_log *log, bool *flush); +int kvm_clear_dirty_log_protect(struct kvm *kvm, + struct kvm_clear_dirty_log *log, bool *flush); void kvm_arch_mmu_enable_log_dirty_pt_masked(struct kvm *kvm, struct kvm_memory_slot *slot, @@ -762,6 +765,8 @@ void kvm_arch_mmu_enable_log_dirty_pt_masked(struct kvm *kvm, int kvm_vm_ioctl_get_dirty_log(struct kvm *kvm, struct kvm_dirty_log *log); +int kvm_vm_ioctl_clear_dirty_log(struct kvm *kvm, + struct kvm_clear_dirty_log *log); int kvm_vm_ioctl_irq_line(struct kvm *kvm, struct kvm_irq_level *irq_level, bool line_status); -- cgit v1.2.3 From 7a86dab8cf2f0fdf508f3555dddfc236623bff60 Mon Sep 17 00:00:00 2001 From: Jim Mattson Date: Fri, 14 Dec 2018 14:34:43 -0800 Subject: kvm: Change offset in kvm_write_guest_offset_cached to unsigned MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Since the offset is added directly to the hva from the gfn_to_hva_cache, a negative offset could result in an out of bounds write. The existing BUG_ON only checks for addresses beyond the end of the gfn_to_hva_cache, not for addresses before the start of the gfn_to_hva_cache. Note that all current call sites have non-negative offsets. Fixes: 4ec6e8636256 ("kvm: Introduce kvm_write_guest_offset_cached()") Reported-by: Cfir Cohen Signed-off-by: Jim Mattson Reviewed-by: Cfir Cohen Reviewed-by: Peter Shier Reviewed-by: Krish Sadhukhan Reviewed-by: Sean Christopherson Signed-off-by: Radim Krčmář --- include/linux/kvm_host.h | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'include/linux') diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index e065aeaae29e..c38cc5eb7e73 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -695,7 +695,8 @@ int kvm_write_guest(struct kvm *kvm, gpa_t gpa, const void *data, int kvm_write_guest_cached(struct kvm *kvm, struct gfn_to_hva_cache *ghc, void *data, unsigned long len); int kvm_write_guest_offset_cached(struct kvm *kvm, struct gfn_to_hva_cache *ghc, - void *data, int offset, unsigned long len); + void *data, unsigned int offset, + 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); int kvm_clear_guest_page(struct kvm *kvm, gfn_t gfn, int offset, int len); -- cgit v1.2.3 From 2bcbd406715dca256912b9c5ae449c7968f15705 Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Thu, 20 Dec 2018 12:25:18 -0800 Subject: Revert "compiler-gcc: disable -ftracer for __noclone functions" The -ftracer optimization was disabled in __noclone as a workaround to GCC duplicating a blob of inline assembly that happened to define a global variable. It has been pointed out that no amount of workarounds can guarantee the compiler won't duplicate inline assembly[1], and that disabling the -ftracer optimization has several unintended and nasty side effects[2][3]. Now that the offending KVM code which required the workaround has been properly fixed and no longer uses __noclone, remove the -ftracer optimization tweak from __noclone. [1] https://lore.kernel.org/lkml/ri6y38lo23g.fsf@suse.cz/T/#u [2] https://lore.kernel.org/lkml/20181218140105.ajuiglkpvstt3qxs@treble/T/#u [3] https://patchwork.kernel.org/patch/8707981/#21817015 This reverts commit 95272c29378ee7dc15f43fa2758cb28a5913a06d. Suggested-by: Andi Kleen Cc: Paolo Bonzini Cc: Nadav Amit Cc: Andi Kleen Cc: Josh Poimboeuf Cc: Martin Jambor Cc: Arnd Bergmann Cc: Steven Rostedt Cc: Miroslav Benes Signed-off-by: Sean Christopherson Reviewed-by: Andi Kleen Reviewed-by: Miguel Ojeda Signed-off-by: Paolo Bonzini --- include/linux/compiler_attributes.h | 9 +-------- 1 file changed, 1 insertion(+), 8 deletions(-) (limited to 'include/linux') diff --git a/include/linux/compiler_attributes.h b/include/linux/compiler_attributes.h index f8c400ba1929..fe07b680dd4a 100644 --- a/include/linux/compiler_attributes.h +++ b/include/linux/compiler_attributes.h @@ -37,7 +37,6 @@ # define __GCC4_has_attribute___designated_init__ 0 # define __GCC4_has_attribute___externally_visible__ 1 # define __GCC4_has_attribute___noclone__ 1 -# define __GCC4_has_attribute___optimize__ 1 # define __GCC4_has_attribute___nonstring__ 0 # define __GCC4_has_attribute___no_sanitize_address__ (__GNUC_MINOR__ >= 8) #endif @@ -163,17 +162,11 @@ /* * Optional: not supported by clang - * Note: icc does not recognize gcc's no-tracer * * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-noclone-function-attribute - * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-optimize-function-attribute */ #if __has_attribute(__noclone__) -# if __has_attribute(__optimize__) -# define __noclone __attribute__((__noclone__, __optimize__("no-tracer"))) -# else -# define __noclone __attribute__((__noclone__)) -# endif +# define __noclone __attribute__((__noclone__)) #else # define __noclone #endif -- cgit v1.2.3