| Message ID | 20240229063726.610065-9-xiaoyao.li@intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | QEMU Guest memfd + QEMU TDX support | expand |
On Thu, Feb 29, 2024 at 01:36:29AM -0500, Xiaoyao Li <xiaoyao.li@intel.com> wrote: > From: Chao Peng <chao.p.peng@linux.intel.com> > > 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@linux.intel.com> > Co-developed-by: Xiaoyao Li <xiaoyao.li@intel.com> > Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com> > > --- > 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 > + */ > + return 0; The reference count leaks. Add memory_region_unref() is needed. Otherwise looks good to me. Reviewed-by: Isaku Yamahata <isaku.yamahata@intel.com>
On 3/5/2024 5:10 PM, Isaku Yamahata wrote: > On Thu, Feb 29, 2024 at 01:36:29AM -0500, > Xiaoyao Li <xiaoyao.li@intel.com> wrote: > >> From: Chao Peng <chao.p.peng@linux.intel.com> >> >> 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@linux.intel.com> >> Co-developed-by: Xiaoyao Li <xiaoyao.li@intel.com> >> Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com> >> >> --- >> 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 >> + */ >> + return 0; > > The reference count leaks. Add memory_region_unref() is needed. thanks for catching it. Will fix it in next version. > Otherwise looks good to me. > Reviewed-by: Isaku Yamahata <isaku.yamahata@intel.com>
On 2/29/2024 14:36, Xiaoyao Li wrote: > From: Chao Peng <chao.p.peng@linux.intel.com> > > 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@linux.intel.com> > Co-developed-by: Xiaoyao Li <xiaoyao.li@intel.com> > Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com> > > --- > 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. > + start, size, to_private ? "private" : "shared"); > + } > + > + memory_region_unref(section.mr); > + return ret; > +} > + > int kvm_cpu_exec(CPUState *cpu) > { > struct kvm_run *run = cpu->kvm_run; > @@ -2970,18 +3032,20 @@ int kvm_cpu_exec(CPUState *cpu) > ret = EXCP_INTERRUPT; > break; > } > - fprintf(stderr, "error: kvm run failed %s\n", > - strerror(-run_ret)); > + if (!(run_ret == -EFAULT && run->exit_reason == KVM_EXIT_MEMORY_FAULT)) { > + fprintf(stderr, "error: kvm run failed %s\n", > + strerror(-run_ret)); > #ifdef TARGET_PPC > - if (run_ret == -EBUSY) { > - fprintf(stderr, > - "This is probably because your SMT is enabled.\n" > - "VCPU can only run on primary threads with all " > - "secondary threads offline.\n"); > - } > + if (run_ret == -EBUSY) { > + fprintf(stderr, > + "This is probably because your SMT is enabled.\n" > + "VCPU can only run on primary threads with all " > + "secondary threads offline.\n"); > + } > #endif > - ret = -1; > - break; > + ret = -1; > + break; > + } > } > > trace_kvm_run_exit(cpu->cpu_index, run->exit_reason); > @@ -3064,6 +3128,16 @@ int kvm_cpu_exec(CPUState *cpu) > break; > } > break; > + case KVM_EXIT_MEMORY_FAULT: > + if (run->memory_fault.flags & ~KVM_MEMORY_EXIT_FLAG_PRIVATE) { > + error_report("KVM_EXIT_MEMORY_FAULT: Unknown flag 0x%" PRIx64, > + (uint64_t)run->memory_fault.flags); > + ret = -1; > + break; > + } > + ret = kvm_convert_memory(run->memory_fault.gpa, run->memory_fault.size, > + run->memory_fault.flags & KVM_MEMORY_EXIT_FLAG_PRIVATE); > + break; > default: > ret = kvm_arch_handle_exit(cpu, run); > break;
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@linux.intel.com> >> >> 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@linux.intel.com> >> Co-developed-by: Xiaoyao Li <xiaoyao.li@intel.com> >> Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com> >> >> --- >> 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!
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 + */ + 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", + start, size, to_private ? "private" : "shared"); + } + + memory_region_unref(section.mr); + return ret; +} + int kvm_cpu_exec(CPUState *cpu) { struct kvm_run *run = cpu->kvm_run; @@ -2970,18 +3032,20 @@ int kvm_cpu_exec(CPUState *cpu) ret = EXCP_INTERRUPT; break; } - fprintf(stderr, "error: kvm run failed %s\n", - strerror(-run_ret)); + if (!(run_ret == -EFAULT && run->exit_reason == KVM_EXIT_MEMORY_FAULT)) { + fprintf(stderr, "error: kvm run failed %s\n", + strerror(-run_ret)); #ifdef TARGET_PPC - if (run_ret == -EBUSY) { - fprintf(stderr, - "This is probably because your SMT is enabled.\n" - "VCPU can only run on primary threads with all " - "secondary threads offline.\n"); - } + if (run_ret == -EBUSY) { + fprintf(stderr, + "This is probably because your SMT is enabled.\n" + "VCPU can only run on primary threads with all " + "secondary threads offline.\n"); + } #endif - ret = -1; - break; + ret = -1; + break; + } } trace_kvm_run_exit(cpu->cpu_index, run->exit_reason); @@ -3064,6 +3128,16 @@ int kvm_cpu_exec(CPUState *cpu) break; } break; + case KVM_EXIT_MEMORY_FAULT: + if (run->memory_fault.flags & ~KVM_MEMORY_EXIT_FLAG_PRIVATE) { + error_report("KVM_EXIT_MEMORY_FAULT: Unknown flag 0x%" PRIx64, + (uint64_t)run->memory_fault.flags); + ret = -1; + break; + } + ret = kvm_convert_memory(run->memory_fault.gpa, run->memory_fault.size, + run->memory_fault.flags & KVM_MEMORY_EXIT_FLAG_PRIVATE); + break; default: ret = kvm_arch_handle_exit(cpu, run); break;