On 3/19/2024 10:14 AM, Wang, Lei wrote:
On 2/29/2024 14:36, Xiaoyao Li wrote:From: Chao Peng <chao.p.peng@xxxxxxxxxxxxxxx> When geeting KVM_EXIT_MEMORY_FAULT exit, it indicates userspace needs to do the memory conversion on the RAMBlock to turn the memory into desired attribute, i.e., private/shared. Currently only KVM_MEMORY_EXIT_FLAG_PRIVATE in flags is valid when KVM_EXIT_MEMORY_FAULT happens. Note, KVM_EXIT_MEMORY_FAULT makes sense only when the RAMBlock has guest_memfd memory backend. Note, KVM_EXIT_MEMORY_FAULT returns with -EFAULT, so special handling is added. When page is converted from shared to private, the original shared memory can be discarded via ram_block_discard_range(). Note, shared memory can be discarded only when it's not back'ed by hugetlb because hugetlb is supposed to be pre-allocated and no need for discarding. Signed-off-by: Chao Peng <chao.p.peng@xxxxxxxxxxxxxxx> Co-developed-by: Xiaoyao Li <xiaoyao.li@xxxxxxxxx> Signed-off-by: Xiaoyao Li <xiaoyao.li@xxxxxxxxx> --- Changes in v4: - open-coded ram_block_discard logic; - change warn_report() to error_report(); (Daniel) --- accel/kvm/kvm-all.c | 94 ++++++++++++++++++++++++++++++++++++++++----- 1 file changed, 84 insertions(+), 10 deletions(-) diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c index 70d482a2c936..87e4275932a7 100644 --- a/accel/kvm/kvm-all.c +++ b/accel/kvm/kvm-all.c @@ -2903,6 +2903,68 @@ static void kvm_eat_signals(CPUState *cpu) } while (sigismember(&chkset, SIG_IPI)); }+static int kvm_convert_memory(hwaddr start, hwaddr size, bool to_private)+{ + MemoryRegionSection section; + ram_addr_t offset; + MemoryRegion *mr; + RAMBlock *rb; + void *addr; + int ret = -1; + + if (!QEMU_PTR_IS_ALIGNED(start, qemu_host_page_size) || + !QEMU_PTR_IS_ALIGNED(size, qemu_host_page_size)) { + return -1; + } + + if (!size) { + return -1; + } + + section = memory_region_find(get_system_memory(), start, size); + mr = section.mr; + if (!mr) { + return -1; + } + + if (memory_region_has_guest_memfd(mr)) { + if (to_private) { + ret = kvm_set_memory_attributes_private(start, size); + } else { + ret = kvm_set_memory_attributes_shared(start, size); + } + + if (ret) { + memory_region_unref(section.mr); + return ret; + } + + addr = memory_region_get_ram_ptr(mr) + section.offset_within_region; + rb = qemu_ram_block_from_host(addr, false, &offset); + + if (to_private) { + if (rb->page_size != qemu_host_page_size) { + /* + * shared memory is back'ed by hugetlb, which is supposed to be + * pre-allocated and doesn't need to be discarded + */Nit: comment indentation is broken here.+ return 0; + } else { + ret = ram_block_discard_range(rb, offset, size); + } + } else { + ret = ram_block_discard_guest_memfd_range(rb, offset, size); + } + } else { + error_report("Convert non guest_memfd backed memory region " + "(0x%"HWADDR_PRIx" ,+ 0x%"HWADDR_PRIx") to %s",Same as above.
Fixed. thanks!
