diff options
| -rw-r--r-- | arch/s390/kernel/crash_dump.c | 54 | ||||
| -rw-r--r-- | tools/testing/selftests/kvm/Makefile | 1 | ||||
| -rw-r--r-- | tools/testing/selftests/kvm/s390x/shared_zeropage_test.c | 111 |
3 files changed, 142 insertions, 24 deletions
diff --git a/arch/s390/kernel/crash_dump.c b/arch/s390/kernel/crash_dump.c index 9863ebe75019..edae13416196 100644 --- a/arch/s390/kernel/crash_dump.c +++ b/arch/s390/kernel/crash_dump.c @@ -451,7 +451,7 @@ static void *nt_final(void *ptr) /* * Initialize ELF header (new kernel) */ -static void *ehdr_init(Elf64_Ehdr *ehdr, int mem_chunk_cnt) +static void *ehdr_init(Elf64_Ehdr *ehdr, int phdr_count) { memset(ehdr, 0, sizeof(*ehdr)); memcpy(ehdr->e_ident, ELFMAG, SELFMAG); @@ -465,11 +465,8 @@ static void *ehdr_init(Elf64_Ehdr *ehdr, int mem_chunk_cnt) ehdr->e_phoff = sizeof(Elf64_Ehdr); ehdr->e_ehsize = sizeof(Elf64_Ehdr); ehdr->e_phentsize = sizeof(Elf64_Phdr); - /* - * Number of memory chunk PT_LOAD program headers plus one kernel - * image PT_LOAD program header plus one PT_NOTE program header. - */ - ehdr->e_phnum = mem_chunk_cnt + 1 + 1; + /* Number of PT_LOAD program headers plus PT_NOTE program header */ + ehdr->e_phnum = phdr_count + 1; return ehdr + 1; } @@ -503,12 +500,14 @@ static int get_mem_chunk_cnt(void) /* * Initialize ELF loads (new kernel) */ -static void loads_init(Elf64_Phdr *phdr) +static void loads_init(Elf64_Phdr *phdr, bool os_info_has_vm) { - unsigned long old_identity_base = os_info_old_value(OS_INFO_IDENTITY_BASE); + unsigned long old_identity_base = 0; phys_addr_t start, end; u64 idx; + if (os_info_has_vm) + old_identity_base = os_info_old_value(OS_INFO_IDENTITY_BASE); for_each_physmem_range(idx, &oldmem_type, &start, &end) { phdr->p_type = PT_LOAD; phdr->p_vaddr = old_identity_base + start; @@ -522,6 +521,11 @@ static void loads_init(Elf64_Phdr *phdr) } } +static bool os_info_has_vm(void) +{ + return os_info_old_value(OS_INFO_KASLR_OFFSET); +} + /* * Prepare PT_LOAD type program header for kernel image region */ @@ -566,7 +570,7 @@ static void *notes_init(Elf64_Phdr *phdr, void *ptr, u64 notes_offset) return ptr; } -static size_t get_elfcorehdr_size(int mem_chunk_cnt) +static size_t get_elfcorehdr_size(int phdr_count) { size_t size; @@ -581,10 +585,8 @@ static size_t get_elfcorehdr_size(int mem_chunk_cnt) size += nt_vmcoreinfo_size(); /* nt_final */ size += sizeof(Elf64_Nhdr); - /* PT_LOAD type program header for kernel text region */ - size += sizeof(Elf64_Phdr); /* PT_LOADS */ - size += mem_chunk_cnt * sizeof(Elf64_Phdr); + size += phdr_count * sizeof(Elf64_Phdr); return size; } @@ -595,8 +597,8 @@ static size_t get_elfcorehdr_size(int mem_chunk_cnt) int elfcorehdr_alloc(unsigned long long *addr, unsigned long long *size) { Elf64_Phdr *phdr_notes, *phdr_loads, *phdr_text; + int mem_chunk_cnt, phdr_text_cnt; size_t alloc_size; - int mem_chunk_cnt; void *ptr, *hdr; u64 hdr_off; @@ -615,12 +617,14 @@ int elfcorehdr_alloc(unsigned long long *addr, unsigned long long *size) } mem_chunk_cnt = get_mem_chunk_cnt(); + phdr_text_cnt = os_info_has_vm() ? 1 : 0; - alloc_size = get_elfcorehdr_size(mem_chunk_cnt); + alloc_size = get_elfcorehdr_size(mem_chunk_cnt + phdr_text_cnt); hdr = kzalloc(alloc_size, GFP_KERNEL); - /* Without elfcorehdr /proc/vmcore cannot be created. Thus creating + /* + * Without elfcorehdr /proc/vmcore cannot be created. Thus creating * a dump with this crash kernel will fail. Panic now to allow other * dump mechanisms to take over. */ @@ -628,21 +632,23 @@ int elfcorehdr_alloc(unsigned long long *addr, unsigned long long *size) panic("s390 kdump allocating elfcorehdr failed"); /* Init elf header */ - ptr = ehdr_init(hdr, mem_chunk_cnt); + phdr_notes = ehdr_init(hdr, mem_chunk_cnt + phdr_text_cnt); /* Init program headers */ - phdr_notes = ptr; - ptr = PTR_ADD(ptr, sizeof(Elf64_Phdr)); - phdr_text = ptr; - ptr = PTR_ADD(ptr, sizeof(Elf64_Phdr)); - phdr_loads = ptr; - ptr = PTR_ADD(ptr, sizeof(Elf64_Phdr) * mem_chunk_cnt); + if (phdr_text_cnt) { + phdr_text = phdr_notes + 1; + phdr_loads = phdr_text + 1; + } else { + phdr_loads = phdr_notes + 1; + } + ptr = PTR_ADD(phdr_loads, sizeof(Elf64_Phdr) * mem_chunk_cnt); /* Init notes */ hdr_off = PTR_DIFF(ptr, hdr); ptr = notes_init(phdr_notes, ptr, ((unsigned long) hdr) + hdr_off); /* Init kernel text program header */ - text_init(phdr_text); + if (phdr_text_cnt) + text_init(phdr_text); /* Init loads */ - loads_init(phdr_loads); + loads_init(phdr_loads, phdr_text_cnt); /* Finalize program headers */ hdr_off = PTR_DIFF(ptr, hdr); *addr = (unsigned long long) hdr; diff --git a/tools/testing/selftests/kvm/Makefile b/tools/testing/selftests/kvm/Makefile index ce8ff8e8ce3a..ac280dcba996 100644 --- a/tools/testing/selftests/kvm/Makefile +++ b/tools/testing/selftests/kvm/Makefile @@ -183,6 +183,7 @@ TEST_GEN_PROGS_s390x += s390x/sync_regs_test TEST_GEN_PROGS_s390x += s390x/tprot TEST_GEN_PROGS_s390x += s390x/cmma_test TEST_GEN_PROGS_s390x += s390x/debug_test +TEST_GEN_PROGS_s390x += s390x/shared_zeropage_test TEST_GEN_PROGS_s390x += demand_paging_test TEST_GEN_PROGS_s390x += dirty_log_test TEST_GEN_PROGS_s390x += guest_print_test diff --git a/tools/testing/selftests/kvm/s390x/shared_zeropage_test.c b/tools/testing/selftests/kvm/s390x/shared_zeropage_test.c new file mode 100644 index 000000000000..bba0d9a6dcc8 --- /dev/null +++ b/tools/testing/selftests/kvm/s390x/shared_zeropage_test.c @@ -0,0 +1,111 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Test shared zeropage handling (with/without storage keys) + * + * Copyright (C) 2024, Red Hat, Inc. + */ +#include <sys/mman.h> + +#include <linux/fs.h> + +#include "test_util.h" +#include "kvm_util.h" +#include "kselftest.h" +#include "ucall_common.h" + +static void set_storage_key(void *addr, uint8_t skey) +{ + asm volatile("sske %0,%1" : : "d" (skey), "a" (addr)); +} + +static void guest_code(void) +{ + /* Issue some storage key instruction. */ + set_storage_key((void *)0, 0x98); + GUEST_DONE(); +} + +/* + * Returns 1 if the shared zeropage is mapped, 0 if something else is mapped. + * Returns < 0 on error or if nothing is mapped. + */ +static int maps_shared_zeropage(int pagemap_fd, void *addr) +{ + struct page_region region; + struct pm_scan_arg arg = { + .start = (uintptr_t)addr, + .end = (uintptr_t)addr + 4096, + .vec = (uintptr_t)®ion, + .vec_len = 1, + .size = sizeof(struct pm_scan_arg), + .category_mask = PAGE_IS_PFNZERO, + .category_anyof_mask = PAGE_IS_PRESENT, + .return_mask = PAGE_IS_PFNZERO, + }; + return ioctl(pagemap_fd, PAGEMAP_SCAN, &arg); +} + +int main(int argc, char *argv[]) +{ + char *mem, *page0, *page1, *page2, tmp; + const size_t pagesize = getpagesize(); + struct kvm_vcpu *vcpu; + struct kvm_vm *vm; + struct ucall uc; + int pagemap_fd; + + ksft_print_header(); + ksft_set_plan(3); + + /* + * We'll use memory that is not mapped into the VM for simplicity. + * Shared zeropages are enabled/disabled per-process. + */ + mem = mmap(0, 3 * pagesize, PROT_READ, MAP_PRIVATE | MAP_ANON, -1, 0); + TEST_ASSERT(mem != MAP_FAILED, "mmap() failed"); + + /* Disable THP. Ignore errors on older kernels. */ + madvise(mem, 3 * pagesize, MADV_NOHUGEPAGE); + + page0 = mem; + page1 = page0 + pagesize; + page2 = page1 + pagesize; + + /* Can we even detect shared zeropages? */ + pagemap_fd = open("/proc/self/pagemap", O_RDONLY); + TEST_REQUIRE(pagemap_fd >= 0); + + tmp = *page0; + asm volatile("" : "+r" (tmp)); + TEST_REQUIRE(maps_shared_zeropage(pagemap_fd, page0) == 1); + + vm = vm_create_with_one_vcpu(&vcpu, guest_code); + + /* Verify that we get the shared zeropage after VM creation. */ + tmp = *page1; + asm volatile("" : "+r" (tmp)); + ksft_test_result(maps_shared_zeropage(pagemap_fd, page1) == 1, + "Shared zeropages should be enabled\n"); + + /* + * Let our VM execute a storage key instruction that should + * unshare all shared zeropages. + */ + vcpu_run(vcpu); + get_ucall(vcpu, &uc); + TEST_ASSERT_EQ(uc.cmd, UCALL_DONE); + + /* Verify that we don't have a shared zeropage anymore. */ + ksft_test_result(!maps_shared_zeropage(pagemap_fd, page1), + "Shared zeropage should be gone\n"); + + /* Verify that we don't get any new shared zeropages. */ + tmp = *page2; + asm volatile("" : "+r" (tmp)); + ksft_test_result(!maps_shared_zeropage(pagemap_fd, page2), + "Shared zeropages should be disabled\n"); + + kvm_vm_free(vm); + + ksft_finished(); +} |