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charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 X-Rspam-User: X-Rspamd-Server: rspam11 X-Rspamd-Queue-Id: 17A884000A X-Stat-Signature: 3eayycd4q8pyzdb6czt15a5eyyt9yhr8 X-HE-Tag: 1775834387-860801 X-HE-Meta: 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 ibS5hRKc 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 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: From: Patrick Roy =0A= =0A= If guest memory is backed using a VMA that does not allow GUP (e.g. a=0A= userspace mapping of guest_memfd when the fd was allocated using=0A= GUEST_MEMFD_FLAG_NO_DIRECT_MAP), then directly loading the test ELF=0A= binary into it via read(2) potentially does not work. To nevertheless=0A= support loading binaries in this cases, do the read(2) syscall using a=0A= bounce buffer, and then memcpy from the bounce buffer into guest memory.=0A= =0A= Signed-off-by: Patrick Roy =0A= Signed-off-by: Nikita Kalyazin =0A= ---=0A= .../testing/selftests/kvm/include/test_util.h | 1 +=0A= tools/testing/selftests/kvm/lib/elf.c | 8 +++----=0A= tools/testing/selftests/kvm/lib/io.c | 23 +++++++++++++++++++=0A= 3 files changed, 28 insertions(+), 4 deletions(-)=0A= =0A= diff --git a/tools/testing/selftests/kvm/include/test_util.h b/tools/testin= g/selftests/kvm/include/test_util.h=0A= index b4872ba8ed12..8140e59b59e5 100644=0A= --- a/tools/testing/selftests/kvm/include/test_util.h=0A= +++ b/tools/testing/selftests/kvm/include/test_util.h=0A= @@ -48,6 +48,7 @@ do { \=0A= =0A= ssize_t test_write(int fd, const void *buf, size_t count);=0A= ssize_t test_read(int fd, void *buf, size_t count);=0A= +ssize_t test_read_bounce(int fd, void *buf, size_t count);=0A= int test_seq_read(const char *path, char **bufp, size_t *sizep);=0A= =0A= void __printf(5, 6) test_assert(bool exp, const char *exp_str,=0A= diff --git a/tools/testing/selftests/kvm/lib/elf.c b/tools/testing/selftest= s/kvm/lib/elf.c=0A= index f34d926d9735..e829fbe0a11e 100644=0A= --- a/tools/testing/selftests/kvm/lib/elf.c=0A= +++ b/tools/testing/selftests/kvm/lib/elf.c=0A= @@ -31,7 +31,7 @@ static void elfhdr_get(const char *filename, Elf64_Ehdr *= hdrp)=0A= * the real size of the ELF header.=0A= */=0A= unsigned char ident[EI_NIDENT];=0A= - test_read(fd, ident, sizeof(ident));=0A= + test_read_bounce(fd, ident, sizeof(ident));=0A= TEST_ASSERT((ident[EI_MAG0] =3D=3D ELFMAG0) && (ident[EI_MAG1] =3D=3D ELF= MAG1)=0A= && (ident[EI_MAG2] =3D=3D ELFMAG2) && (ident[EI_MAG3] =3D=3D ELFMAG3),= =0A= "ELF MAGIC Mismatch,\n"=0A= @@ -79,7 +79,7 @@ static void elfhdr_get(const char *filename, Elf64_Ehdr *= hdrp)=0A= offset_rv =3D lseek(fd, 0, SEEK_SET);=0A= TEST_ASSERT(offset_rv =3D=3D 0, "Seek to ELF header failed,\n"=0A= " rv: %zi expected: %i", offset_rv, 0);=0A= - test_read(fd, hdrp, sizeof(*hdrp));=0A= + test_read_bounce(fd, hdrp, sizeof(*hdrp));=0A= TEST_ASSERT(hdrp->e_phentsize =3D=3D sizeof(Elf64_Phdr),=0A= "Unexpected physical header size,\n"=0A= " hdrp->e_phentsize: %x\n"=0A= @@ -146,7 +146,7 @@ void kvm_vm_elf_load(struct kvm_vm *vm, const char *fil= ename)=0A= =0A= /* Read in the program header. */=0A= Elf64_Phdr phdr;=0A= - test_read(fd, &phdr, sizeof(phdr));=0A= + test_read_bounce(fd, &phdr, sizeof(phdr));=0A= =0A= /* Skip if this header doesn't describe a loadable segment. */=0A= if (phdr.p_type !=3D PT_LOAD)=0A= @@ -187,7 +187,7 @@ void kvm_vm_elf_load(struct kvm_vm *vm, const char *fil= ename)=0A= " expected: 0x%jx",=0A= n1, errno, (intmax_t) offset_rv,=0A= (intmax_t) phdr.p_offset);=0A= - test_read(fd, addr_gva2hva(vm, phdr.p_vaddr),=0A= + test_read_bounce(fd, addr_gva2hva(vm, phdr.p_vaddr),=0A= phdr.p_filesz);=0A= }=0A= }=0A= diff --git a/tools/testing/selftests/kvm/lib/io.c b/tools/testing/selftests= /kvm/lib/io.c=0A= index fedb2a741f0b..60613dce6cfd 100644=0A= --- a/tools/testing/selftests/kvm/lib/io.c=0A= +++ b/tools/testing/selftests/kvm/lib/io.c=0A= @@ -155,3 +155,26 @@ ssize_t test_read(int fd, void *buf, size_t count)=0A= =0A= return num_read;=0A= }=0A= +=0A= +/* Test read via intermediary buffer=0A= + *=0A= + * Same as test_read, except read(2)s happen into a bounce buffer that is = memcpy'd=0A= + * to buf. For use with buffers that cannot be GUP'd (e.g. guest_memfd VMA= s if=0A= + * guest_memfd was created with GUEST_MEMFD_FLAG_NO_DIRECT_MAP).=0A= + */=0A= +ssize_t test_read_bounce(int fd, void *buf, size_t count)=0A= +{=0A= + void *bounce_buffer;=0A= + ssize_t num_read;=0A= +=0A= + TEST_ASSERT(count > 0, "Unexpected count, count: %zu", count);=0A= +=0A= + bounce_buffer =3D malloc(count);=0A= + TEST_ASSERT(bounce_buffer !=3D NULL, "Failed to allocate bounce buffer");= =0A= +=0A= + num_read =3D test_read(fd, bounce_buffer, count);=0A= + memcpy(buf, bounce_buffer, num_read);=0A= + free(bounce_buffer);=0A= +=0A= + return num_read;=0A= +}=0A= -- =0A= 2.50.1=0A= =0A=