Setting skip_dump on a MemoryRegion allows us to modify one specific code path, but the restriction we're trying to address encompasses more than that. If we have a RAM MemoryRegion backed by a physical device, it not only restricts our ability to dump that region, but also affects how we should manipulate it. Here we recognize that MemoryRegions do not change to sometimes allow dumps and other times not, so we replace setting the skip_dump flag with a new initializer so that we know exactly the type of region to which we're applying this behavior. Signed-off-by: Alex Williamson <alex.williamson@redhat.com> Acked-by: Paolo Bonzini <pbonzini@redhat.com>
210 lines
6.9 KiB
C
210 lines
6.9 KiB
C
/*
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* DMA memory preregistration
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*
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* Authors:
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* Alexey Kardashevskiy <aik@ozlabs.ru>
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*
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* This work is licensed under the terms of the GNU GPL, version 2. See
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* the COPYING file in the top-level directory.
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*/
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#include "qemu/osdep.h"
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#include "cpu.h"
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#include <sys/ioctl.h>
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#include <linux/vfio.h>
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#include "hw/vfio/vfio-common.h"
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#include "hw/hw.h"
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#include "qemu/error-report.h"
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#include "trace.h"
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static bool vfio_prereg_listener_skipped_section(MemoryRegionSection *section)
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{
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if (memory_region_is_iommu(section->mr)) {
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hw_error("Cannot possibly preregister IOMMU memory");
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}
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return !memory_region_is_ram(section->mr) ||
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memory_region_is_ram_device(section->mr);
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}
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static void *vfio_prereg_gpa_to_vaddr(MemoryRegionSection *section, hwaddr gpa)
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{
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return memory_region_get_ram_ptr(section->mr) +
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section->offset_within_region +
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(gpa - section->offset_within_address_space);
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}
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static void vfio_prereg_listener_region_add(MemoryListener *listener,
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MemoryRegionSection *section)
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{
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VFIOContainer *container = container_of(listener, VFIOContainer,
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prereg_listener);
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const hwaddr gpa = section->offset_within_address_space;
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hwaddr end;
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int ret;
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hwaddr page_mask = qemu_real_host_page_mask;
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struct vfio_iommu_spapr_register_memory reg = {
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.argsz = sizeof(reg),
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.flags = 0,
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};
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if (vfio_prereg_listener_skipped_section(section)) {
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trace_vfio_prereg_listener_region_add_skip(
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section->offset_within_address_space,
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section->offset_within_address_space +
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int128_get64(int128_sub(section->size, int128_one())));
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return;
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}
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if (unlikely((section->offset_within_address_space & ~page_mask) ||
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(section->offset_within_region & ~page_mask) ||
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(int128_get64(section->size) & ~page_mask))) {
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error_report("%s received unaligned region", __func__);
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return;
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}
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end = section->offset_within_address_space + int128_get64(section->size);
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if (gpa >= end) {
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return;
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}
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memory_region_ref(section->mr);
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reg.vaddr = (uintptr_t) vfio_prereg_gpa_to_vaddr(section, gpa);
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reg.size = end - gpa;
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ret = ioctl(container->fd, VFIO_IOMMU_SPAPR_REGISTER_MEMORY, ®);
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trace_vfio_prereg_register(reg.vaddr, reg.size, ret ? -errno : 0);
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if (ret) {
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/*
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* On the initfn path, store the first error in the container so we
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* can gracefully fail. Runtime, there's not much we can do other
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* than throw a hardware error.
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*/
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if (!container->initialized) {
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if (!container->error) {
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container->error = ret;
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}
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} else {
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hw_error("vfio: Memory registering failed, unable to continue");
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}
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}
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}
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static void vfio_prereg_listener_region_del(MemoryListener *listener,
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MemoryRegionSection *section)
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{
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VFIOContainer *container = container_of(listener, VFIOContainer,
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prereg_listener);
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const hwaddr gpa = section->offset_within_address_space;
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hwaddr end;
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int ret;
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hwaddr page_mask = qemu_real_host_page_mask;
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struct vfio_iommu_spapr_register_memory reg = {
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.argsz = sizeof(reg),
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.flags = 0,
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};
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if (vfio_prereg_listener_skipped_section(section)) {
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trace_vfio_prereg_listener_region_del_skip(
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section->offset_within_address_space,
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section->offset_within_address_space +
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int128_get64(int128_sub(section->size, int128_one())));
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return;
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}
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if (unlikely((section->offset_within_address_space & ~page_mask) ||
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(section->offset_within_region & ~page_mask) ||
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(int128_get64(section->size) & ~page_mask))) {
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error_report("%s received unaligned region", __func__);
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return;
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}
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end = section->offset_within_address_space + int128_get64(section->size);
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if (gpa >= end) {
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return;
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}
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reg.vaddr = (uintptr_t) vfio_prereg_gpa_to_vaddr(section, gpa);
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reg.size = end - gpa;
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ret = ioctl(container->fd, VFIO_IOMMU_SPAPR_UNREGISTER_MEMORY, ®);
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trace_vfio_prereg_unregister(reg.vaddr, reg.size, ret ? -errno : 0);
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}
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const MemoryListener vfio_prereg_listener = {
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.region_add = vfio_prereg_listener_region_add,
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.region_del = vfio_prereg_listener_region_del,
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};
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int vfio_spapr_create_window(VFIOContainer *container,
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MemoryRegionSection *section,
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hwaddr *pgsize)
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{
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int ret;
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unsigned pagesize = memory_region_iommu_get_min_page_size(section->mr);
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unsigned entries, pages;
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struct vfio_iommu_spapr_tce_create create = { .argsz = sizeof(create) };
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/*
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* FIXME: For VFIO iommu types which have KVM acceleration to
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* avoid bouncing all map/unmaps through qemu this way, this
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* would be the right place to wire that up (tell the KVM
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* device emulation the VFIO iommu handles to use).
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*/
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create.window_size = int128_get64(section->size);
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create.page_shift = ctz64(pagesize);
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/*
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* SPAPR host supports multilevel TCE tables, there is some
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* heuristic to decide how many levels we want for our table:
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* 0..64 = 1; 65..4096 = 2; 4097..262144 = 3; 262145.. = 4
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*/
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entries = create.window_size >> create.page_shift;
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pages = MAX((entries * sizeof(uint64_t)) / getpagesize(), 1);
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pages = MAX(pow2ceil(pages) - 1, 1); /* Round up */
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create.levels = ctz64(pages) / 6 + 1;
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ret = ioctl(container->fd, VFIO_IOMMU_SPAPR_TCE_CREATE, &create);
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if (ret) {
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error_report("Failed to create a window, ret = %d (%m)", ret);
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return -errno;
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}
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if (create.start_addr != section->offset_within_address_space) {
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vfio_spapr_remove_window(container, create.start_addr);
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error_report("Host doesn't support DMA window at %"HWADDR_PRIx", must be %"PRIx64,
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section->offset_within_address_space,
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(uint64_t)create.start_addr);
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return -EINVAL;
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}
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trace_vfio_spapr_create_window(create.page_shift,
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create.window_size,
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create.start_addr);
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*pgsize = pagesize;
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return 0;
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}
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int vfio_spapr_remove_window(VFIOContainer *container,
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hwaddr offset_within_address_space)
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{
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struct vfio_iommu_spapr_tce_remove remove = {
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.argsz = sizeof(remove),
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.start_addr = offset_within_address_space,
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};
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int ret;
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ret = ioctl(container->fd, VFIO_IOMMU_SPAPR_TCE_REMOVE, &remove);
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if (ret) {
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error_report("Failed to remove window at %"PRIx64,
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(uint64_t)remove.start_addr);
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return -errno;
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}
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trace_vfio_spapr_remove_window(offset_within_address_space);
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return 0;
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}
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