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kvm: Enable KVM_SET_USER_MEMORY_REGION2 for memslot
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Switch to KVM_SET_USER_MEMORY_REGION2 when supported by KVM.

With KVM_SET_USER_MEMORY_REGION2, QEMU can set up memory region that
backend'ed both by hva-based shared memory and guest memfd based private
memory.

Signed-off-by: Chao Peng <chao.p.peng@linux.intel.com>
Co-developed-by: Xiaoyao Li <xiaoyao.li@intel.com>
Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com>
Message-ID: <20240320083945.991426-10-michael.roth@amd.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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@chao-p @bonzini
chao-p authored and bonzini committed Apr 23, 2024
1 parent 15f7a80 commit ce5a983
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Showing 3 changed files with 41 additions and 9 deletions.
46 changes: 38 additions & 8 deletions accel/kvm/kvm-all.c
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Original file line number Diff line number Diff line change
Expand Up @@ -284,35 +284,58 @@ int kvm_physical_memory_addr_from_host(KVMState *s, void *ram,
static int kvm_set_user_memory_region(KVMMemoryListener *kml, KVMSlot *slot, bool new)
{
KVMState *s = kvm_state;
struct kvm_userspace_memory_region mem;
struct kvm_userspace_memory_region2 mem;
int ret;

mem.slot = slot->slot | (kml->as_id << 16);
mem.guest_phys_addr = slot->start_addr;
mem.userspace_addr = (unsigned long)slot->ram;
mem.flags = slot->flags;
mem.guest_memfd = slot->guest_memfd;
mem.guest_memfd_offset = slot->guest_memfd_offset;

if (slot->memory_size && !new && (mem.flags ^ slot->old_flags) & KVM_MEM_READONLY) {
/* Set the slot size to 0 before setting the slot to the desired
* value. This is needed based on KVM commit 75d61fbc. */
mem.memory_size = 0;
ret = kvm_vm_ioctl(s, KVM_SET_USER_MEMORY_REGION, &mem);

if (kvm_guest_memfd_supported) {
ret = kvm_vm_ioctl(s, KVM_SET_USER_MEMORY_REGION2, &mem);
} else {
ret = kvm_vm_ioctl(s, KVM_SET_USER_MEMORY_REGION, &mem);
}
if (ret < 0) {
goto err;
}
}
mem.memory_size = slot->memory_size;
ret = kvm_vm_ioctl(s, KVM_SET_USER_MEMORY_REGION, &mem);
if (kvm_guest_memfd_supported) {
ret = kvm_vm_ioctl(s, KVM_SET_USER_MEMORY_REGION2, &mem);
} else {
ret = kvm_vm_ioctl(s, KVM_SET_USER_MEMORY_REGION, &mem);
}
slot->old_flags = mem.flags;
err:
trace_kvm_set_user_memory(mem.slot >> 16, (uint16_t)mem.slot, mem.flags,
mem.guest_phys_addr, mem.memory_size,
mem.userspace_addr, ret);
mem.userspace_addr, mem.guest_memfd,
mem.guest_memfd_offset, ret);
if (ret < 0) {
error_report("%s: KVM_SET_USER_MEMORY_REGION failed, slot=%d,"
" start=0x%" PRIx64 ", size=0x%" PRIx64 ": %s",
__func__, mem.slot, slot->start_addr,
(uint64_t)mem.memory_size, strerror(errno));
if (kvm_guest_memfd_supported) {
error_report("%s: KVM_SET_USER_MEMORY_REGION2 failed, slot=%d,"
" start=0x%" PRIx64 ", size=0x%" PRIx64 ","
" flags=0x%" PRIx32 ", guest_memfd=%" PRId32 ","
" guest_memfd_offset=0x%" PRIx64 ": %s",
__func__, mem.slot, slot->start_addr,
(uint64_t)mem.memory_size, mem.flags,
mem.guest_memfd, (uint64_t)mem.guest_memfd_offset,
strerror(errno));
} else {
error_report("%s: KVM_SET_USER_MEMORY_REGION failed, slot=%d,"
" start=0x%" PRIx64 ", size=0x%" PRIx64 ": %s",
__func__, mem.slot, slot->start_addr,
(uint64_t)mem.memory_size, strerror(errno));
}
}
return ret;
}
Expand Down Expand Up @@ -467,6 +490,10 @@ static int kvm_mem_flags(MemoryRegion *mr)
if (readonly && kvm_readonly_mem_allowed) {
flags |= KVM_MEM_READONLY;
}
if (memory_region_has_guest_memfd(mr)) {
assert(kvm_guest_memfd_supported);
flags |= KVM_MEM_GUEST_MEMFD;
}
return flags;
}

Expand Down Expand Up @@ -1394,6 +1421,9 @@ static void kvm_set_phys_mem(KVMMemoryListener *kml,
mem->ram_start_offset = ram_start_offset;
mem->ram = ram;
mem->flags = kvm_mem_flags(mr);
mem->guest_memfd = mr->ram_block->guest_memfd;
mem->guest_memfd_offset = (uint8_t*)ram - mr->ram_block->host;

kvm_slot_init_dirty_bitmap(mem);
err = kvm_set_user_memory_region(kml, mem, true);
if (err) {
Expand Down
2 changes: 1 addition & 1 deletion accel/kvm/trace-events
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Original file line number Diff line number Diff line change
Expand Up @@ -15,7 +15,7 @@ kvm_irqchip_update_msi_route(int virq) "Updating MSI route virq=%d"
kvm_irqchip_release_virq(int virq) "virq %d"
kvm_set_ioeventfd_mmio(int fd, uint64_t addr, uint32_t val, bool assign, uint32_t size, bool datamatch) "fd: %d @0x%" PRIx64 " val=0x%x assign: %d size: %d match: %d"
kvm_set_ioeventfd_pio(int fd, uint16_t addr, uint32_t val, bool assign, uint32_t size, bool datamatch) "fd: %d @0x%x val=0x%x assign: %d size: %d match: %d"
kvm_set_user_memory(uint16_t as, uint16_t slot, uint32_t flags, uint64_t guest_phys_addr, uint64_t memory_size, uint64_t userspace_addr, int ret) "AddrSpace#%d Slot#%d flags=0x%x gpa=0x%"PRIx64 " size=0x%"PRIx64 " ua=0x%"PRIx64 " ret=%d"
kvm_set_user_memory(uint16_t as, uint16_t slot, uint32_t flags, uint64_t guest_phys_addr, uint64_t memory_size, uint64_t userspace_addr, uint32_t fd, uint64_t fd_offset, int ret) "AddrSpace#%d Slot#%d flags=0x%x gpa=0x%"PRIx64 " size=0x%"PRIx64 " ua=0x%"PRIx64 " guest_memfd=%d" " guest_memfd_offset=0x%" PRIx64 " ret=%d"
kvm_clear_dirty_log(uint32_t slot, uint64_t start, uint32_t size) "slot#%"PRId32" start 0x%"PRIx64" size 0x%"PRIx32
kvm_resample_fd_notify(int gsi) "gsi %d"
kvm_dirty_ring_full(int id) "vcpu %d"
Expand Down
2 changes: 2 additions & 0 deletions include/sysemu/kvm_int.h
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Original file line number Diff line number Diff line change
Expand Up @@ -30,6 +30,8 @@ typedef struct KVMSlot
int as_id;
/* Cache of the offset in ram address space */
ram_addr_t ram_start_offset;
int guest_memfd;
hwaddr guest_memfd_offset;
} KVMSlot;

typedef struct KVMMemoryUpdate {
Expand Down

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