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charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 X-Rspamd-Server: rspam12 X-Rspamd-Queue-Id: EBC5EC000A X-Stat-Signature: igyayqdjtj6tokpbtdejrhpm67jigr9p X-Rspam-User: X-HE-Tag: 1758727375-360869 X-HE-Meta: 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 L1GsgzUa ProHbfbaFdEJtTCsMXo18oU6VPyokA4kAdOjQ3BilRdUAMszrmCsgcvqPJG9cz1RFQyDUDHFVBhtrNdSwY0LlcQemjzIUReZOHZOnNl6r7UI6+1gWpRJFsglcshZStdnhkOZBNylt2HsRhTYGQaSAFd/kXZ/6OU561Q90V9RGiK5IfxHVUmHyerBb2uoAyw6ZE48kIgakXWCx84W9tWjz2/tWGVf0PTL+EDaE7r22XXarLQQNpnE9PQUQZQRzaRyBMMrAM+0ybLnS/sgGYAofBGWvTl0HjIvtmZKPohhBON3xkNMRfUsZIU4bNhtUwt4+rvRtpXxGSz0q9sZXpfP1uleR8k/NBaXvqrtctueUT4YZVj+m+orVlQmp8ZcZwOJVaWaG X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: 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= KVM_GMEM_NO_DIRECT_MAP), then directly loading the test ELF binary into=0A= it via read(2) potentially does not work. To nevertheless support=0A= loading binaries in this cases, do the read(2) syscall using a bounce=0A= buffer, and then memcpy from the bounce buffer into guest memory.=0A= =0A= Signed-off-by: Patrick Roy =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 c6ef895fbd9a..0409b7b96c94 100644=0A= --- a/tools/testing/selftests/kvm/include/test_util.h=0A= +++ b/tools/testing/selftests/kvm/include/test_util.h=0A= @@ -46,6 +46,7 @@ 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..74419becc8bc 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 >=3D 0, "Unexpected count, count: %li", 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= 2.51.0=0A= =0A=