| Message ID | 20231105163040.14904-26-pbonzini@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | KVM: guest_memfd() and per-page attributes | expand |
On Sun, Nov 5, 2023 at 4:34 PM Paolo Bonzini <pbonzini@redhat.com> wrote: > > From: Vishal Annapurve <vannapurve@google.com> > > Add helpers to convert memory between private and shared via KVM's > memory attributes, as well as helpers to free/allocate guest_memfd memory > via fallocate(). Userspace, i.e. tests, is NOT required to do fallocate() > when converting memory, as the attributes are the single source of true. nit: true->truth > Provide allocate() helpers so that tests can mimic a userspace that frees > private memory on conversion, e.g. to prioritize memory usage over > performance. > > Signed-off-by: Vishal Annapurve <vannapurve@google.com> > Co-developed-by: Sean Christopherson <seanjc@google.com> > Signed-off-by: Sean Christopherson <seanjc@google.com> > Message-Id: <20231027182217.3615211-28-seanjc@google.com> > Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> > --- > .../selftests/kvm/include/kvm_util_base.h | 48 +++++++++++++++++++ > tools/testing/selftests/kvm/lib/kvm_util.c | 28 +++++++++++ > 2 files changed, 76 insertions(+) > > diff --git a/tools/testing/selftests/kvm/include/kvm_util_base.h b/tools/testing/selftests/kvm/include/kvm_util_base.h > index 9f861182c02a..1441fca6c273 100644 > --- a/tools/testing/selftests/kvm/include/kvm_util_base.h > +++ b/tools/testing/selftests/kvm/include/kvm_util_base.h > @@ -333,6 +333,54 @@ static inline void vm_enable_cap(struct kvm_vm *vm, uint32_t cap, uint64_t arg0) > vm_ioctl(vm, KVM_ENABLE_CAP, &enable_cap); > } > > +static inline void vm_set_memory_attributes(struct kvm_vm *vm, uint64_t gpa, > + uint64_t size, uint64_t attributes) > +{ > + struct kvm_memory_attributes attr = { > + .attributes = attributes, > + .address = gpa, > + .size = size, > + .flags = 0, > + }; > + > + /* > + * KVM_SET_MEMORY_ATTRIBUTES overwrites _all_ attributes. These flows > + * need significant enhancements to support multiple attributes. > + */ > + TEST_ASSERT(!attributes || attributes == KVM_MEMORY_ATTRIBUTE_PRIVATE, > + "Update me to support multiple attributes!"); > + > + vm_ioctl(vm, KVM_SET_MEMORY_ATTRIBUTES, &attr); > +} > + > + > +static inline void vm_mem_set_private(struct kvm_vm *vm, uint64_t gpa, > + uint64_t size) > +{ > + vm_set_memory_attributes(vm, gpa, size, KVM_MEMORY_ATTRIBUTE_PRIVATE); > +} > + > +static inline void vm_mem_set_shared(struct kvm_vm *vm, uint64_t gpa, > + uint64_t size) > +{ > + vm_set_memory_attributes(vm, gpa, size, 0); > +} > + > +void vm_guest_mem_fallocate(struct kvm_vm *vm, uint64_t gpa, uint64_t size, > + bool punch_hole); > + > +static inline void vm_guest_mem_punch_hole(struct kvm_vm *vm, uint64_t gpa, > + uint64_t size) > +{ > + vm_guest_mem_fallocate(vm, gpa, size, true); > +} > + > +static inline void vm_guest_mem_allocate(struct kvm_vm *vm, uint64_t gpa, > + uint64_t size) > +{ > + vm_guest_mem_fallocate(vm, gpa, size, false); > +} > + > void vm_enable_dirty_ring(struct kvm_vm *vm, uint32_t ring_size); > const char *vm_guest_mode_string(uint32_t i); > > diff --git a/tools/testing/selftests/kvm/lib/kvm_util.c b/tools/testing/selftests/kvm/lib/kvm_util.c > index b63500fca627..95a553400ea9 100644 > --- a/tools/testing/selftests/kvm/lib/kvm_util.c > +++ b/tools/testing/selftests/kvm/lib/kvm_util.c > @@ -1167,6 +1167,34 @@ void vm_mem_region_delete(struct kvm_vm *vm, uint32_t slot) > __vm_mem_region_delete(vm, memslot2region(vm, slot), true); > } > > +void vm_guest_mem_fallocate(struct kvm_vm *vm, uint64_t base, uint64_t size, > + bool punch_hole) > +{ > + const int mode = FALLOC_FL_KEEP_SIZE | (punch_hole ? FALLOC_FL_PUNCH_HOLE : 0); > + struct userspace_mem_region *region; > + uint64_t end = base + size; > + uint64_t gpa, len; > + off_t fd_offset; > + int ret; > + > + for (gpa = base; gpa < end; gpa += len) { > + uint64_t offset; > + > + region = userspace_mem_region_find(vm, gpa, gpa); > + TEST_ASSERT(region && region->region.flags & KVM_MEM_GUEST_MEMFD, > + "Private memory region not found for GPA 0x%lx", gpa); > + > + offset = (gpa - region->region.guest_phys_addr); nit: why the parentheses? > + fd_offset = region->region.guest_memfd_offset + offset; > + len = min_t(uint64_t, end - gpa, region->region.memory_size - offset); > + > + ret = fallocate(region->region.guest_memfd, mode, fd_offset, len); > + TEST_ASSERT(!ret, "fallocate() failed to %s at %lx (len = %lu), fd = %d, mode = %x, offset = %lx\n", > + punch_hole ? "punch hole" : "allocate", gpa, len, > + region->region.guest_memfd, mode, fd_offset); > + } > +} > + > /* Returns the size of a vCPU's kvm_run structure. */ > static int vcpu_mmap_sz(void) > { Nits aside: Reviewed-by: Fuad Tabba <tabba@google.com> Tested-by: Fuad Tabba <tabba@google.com> Cheers, /fuad > -- > 2.39.1 > >
On Mon, Nov 06, 2023, Fuad Tabba wrote: > On Sun, Nov 5, 2023 at 4:34 PM Paolo Bonzini <pbonzini@redhat.com> wrote: > > +void vm_guest_mem_fallocate(struct kvm_vm *vm, uint64_t base, uint64_t size, > > + bool punch_hole) > > +{ > > + const int mode = FALLOC_FL_KEEP_SIZE | (punch_hole ? FALLOC_FL_PUNCH_HOLE : 0); > > + struct userspace_mem_region *region; > > + uint64_t end = base + size; > > + uint64_t gpa, len; > > + off_t fd_offset; > > + int ret; > > + > > + for (gpa = base; gpa < end; gpa += len) { > > + uint64_t offset; > > + > > + region = userspace_mem_region_find(vm, gpa, gpa); > > + TEST_ASSERT(region && region->region.flags & KVM_MEM_GUEST_MEMFD, > > + "Private memory region not found for GPA 0x%lx", gpa); > > + > > + offset = (gpa - region->region.guest_phys_addr); > > nit: why the parentheses? I simply forgot to remove them when I changed the function to support spanning multiple memslots, i.e. when the code went from this fd_offset = region->region.gmem_offset + (gpa - region->region.guest_phys_addr); to what you see above.
On Mon, Nov 6, 2023 at 4:13 PM Sean Christopherson <seanjc@google.com> wrote: > > On Mon, Nov 06, 2023, Fuad Tabba wrote: > > On Sun, Nov 5, 2023 at 4:34 PM Paolo Bonzini <pbonzini@redhat.com> wrote: > > > +void vm_guest_mem_fallocate(struct kvm_vm *vm, uint64_t base, uint64_t size, > > > + bool punch_hole) > > > +{ > > > + const int mode = FALLOC_FL_KEEP_SIZE | (punch_hole ? FALLOC_FL_PUNCH_HOLE : 0); > > > + struct userspace_mem_region *region; > > > + uint64_t end = base + size; > > > + uint64_t gpa, len; > > > + off_t fd_offset; > > > + int ret; > > > + > > > + for (gpa = base; gpa < end; gpa += len) { > > > + uint64_t offset; > > > + > > > + region = userspace_mem_region_find(vm, gpa, gpa); > > > + TEST_ASSERT(region && region->region.flags & KVM_MEM_GUEST_MEMFD, > > > + "Private memory region not found for GPA 0x%lx", gpa); > > > + > > > + offset = (gpa - region->region.guest_phys_addr); > > > > nit: why the parentheses? > > I simply forgot to remove them when I changed the function to support spanning > multiple memslots, i.e. when the code went from this > > fd_offset = region->region.gmem_offset + > (gpa - region->region.guest_phys_addr); > > to what you see above. I wasn't actually expecting an answer, but I literally _did_ ask for it :) Thanks, /fuad
diff --git a/tools/testing/selftests/kvm/include/kvm_util_base.h b/tools/testing/selftests/kvm/include/kvm_util_base.h index 9f861182c02a..1441fca6c273 100644 --- a/tools/testing/selftests/kvm/include/kvm_util_base.h +++ b/tools/testing/selftests/kvm/include/kvm_util_base.h @@ -333,6 +333,54 @@ static inline void vm_enable_cap(struct kvm_vm *vm, uint32_t cap, uint64_t arg0) vm_ioctl(vm, KVM_ENABLE_CAP, &enable_cap); } +static inline void vm_set_memory_attributes(struct kvm_vm *vm, uint64_t gpa, + uint64_t size, uint64_t attributes) +{ + struct kvm_memory_attributes attr = { + .attributes = attributes, + .address = gpa, + .size = size, + .flags = 0, + }; + + /* + * KVM_SET_MEMORY_ATTRIBUTES overwrites _all_ attributes. These flows + * need significant enhancements to support multiple attributes. + */ + TEST_ASSERT(!attributes || attributes == KVM_MEMORY_ATTRIBUTE_PRIVATE, + "Update me to support multiple attributes!"); + + vm_ioctl(vm, KVM_SET_MEMORY_ATTRIBUTES, &attr); +} + + +static inline void vm_mem_set_private(struct kvm_vm *vm, uint64_t gpa, + uint64_t size) +{ + vm_set_memory_attributes(vm, gpa, size, KVM_MEMORY_ATTRIBUTE_PRIVATE); +} + +static inline void vm_mem_set_shared(struct kvm_vm *vm, uint64_t gpa, + uint64_t size) +{ + vm_set_memory_attributes(vm, gpa, size, 0); +} + +void vm_guest_mem_fallocate(struct kvm_vm *vm, uint64_t gpa, uint64_t size, + bool punch_hole); + +static inline void vm_guest_mem_punch_hole(struct kvm_vm *vm, uint64_t gpa, + uint64_t size) +{ + vm_guest_mem_fallocate(vm, gpa, size, true); +} + +static inline void vm_guest_mem_allocate(struct kvm_vm *vm, uint64_t gpa, + uint64_t size) +{ + vm_guest_mem_fallocate(vm, gpa, size, false); +} + void vm_enable_dirty_ring(struct kvm_vm *vm, uint32_t ring_size); const char *vm_guest_mode_string(uint32_t i); diff --git a/tools/testing/selftests/kvm/lib/kvm_util.c b/tools/testing/selftests/kvm/lib/kvm_util.c index b63500fca627..95a553400ea9 100644 --- a/tools/testing/selftests/kvm/lib/kvm_util.c +++ b/tools/testing/selftests/kvm/lib/kvm_util.c @@ -1167,6 +1167,34 @@ void vm_mem_region_delete(struct kvm_vm *vm, uint32_t slot) __vm_mem_region_delete(vm, memslot2region(vm, slot), true); } +void vm_guest_mem_fallocate(struct kvm_vm *vm, uint64_t base, uint64_t size, + bool punch_hole) +{ + const int mode = FALLOC_FL_KEEP_SIZE | (punch_hole ? FALLOC_FL_PUNCH_HOLE : 0); + struct userspace_mem_region *region; + uint64_t end = base + size; + uint64_t gpa, len; + off_t fd_offset; + int ret; + + for (gpa = base; gpa < end; gpa += len) { + uint64_t offset; + + region = userspace_mem_region_find(vm, gpa, gpa); + TEST_ASSERT(region && region->region.flags & KVM_MEM_GUEST_MEMFD, + "Private memory region not found for GPA 0x%lx", gpa); + + offset = (gpa - region->region.guest_phys_addr); + fd_offset = region->region.guest_memfd_offset + offset; + len = min_t(uint64_t, end - gpa, region->region.memory_size - offset); + + ret = fallocate(region->region.guest_memfd, mode, fd_offset, len); + TEST_ASSERT(!ret, "fallocate() failed to %s at %lx (len = %lu), fd = %d, mode = %x, offset = %lx\n", + punch_hole ? "punch hole" : "allocate", gpa, len, + region->region.guest_memfd, mode, fd_offset); + } +} + /* Returns the size of a vCPU's kvm_run structure. */ static int vcpu_mmap_sz(void) {