| Message ID | 20220921100729.2942008-2-Jason@zx2c4.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v8,1/2] target/s390x: support SHA-512 extensions | expand |
On 21.09.22 12:07, Jason A. Donenfeld wrote: > In order for hosts running inside of TCG to initialize the kernel's > random number generator, we should support the PRNO_TRNG instruction, > backed in the usual way with the qemu_guest_getrandom helper. This is > confirmed working on Linux 5.19. > > Cc: Thomas Huth <thuth@redhat.com> > Cc: David Hildenbrand <david@redhat.com> > Cc: Christian Borntraeger <borntraeger@linux.ibm.com> > Cc: Richard Henderson <richard.henderson@linaro.org> > Cc: Cornelia Huck <cohuck@redhat.com> > Cc: Harald Freudenberger <freude@linux.ibm.com> > Cc: Holger Dengler <dengler@linux.ibm.com> > Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com> Thanks! Reviewed-by: David Hildenbrand <david@redhat.com>
On 21/09/2022 12.07, Jason A. Donenfeld wrote: > In order for hosts running inside of TCG to initialize the kernel's > random number generator, we should support the PRNO_TRNG instruction, > backed in the usual way with the qemu_guest_getrandom helper. This is > confirmed working on Linux 5.19. > > Cc: Thomas Huth <thuth@redhat.com> > Cc: David Hildenbrand <david@redhat.com> > Cc: Christian Borntraeger <borntraeger@linux.ibm.com> > Cc: Richard Henderson <richard.henderson@linaro.org> > Cc: Cornelia Huck <cohuck@redhat.com> > Cc: Harald Freudenberger <freude@linux.ibm.com> > Cc: Holger Dengler <dengler@linux.ibm.com> > Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com> > --- > target/s390x/gen-features.c | 1 + > target/s390x/tcg/crypto_helper.c | 30 ++++++++++++++++++++++++++++++ > 2 files changed, 31 insertions(+) > > diff --git a/target/s390x/gen-features.c b/target/s390x/gen-features.c > index 14a7f2ae90..aaade67574 100644 > --- a/target/s390x/gen-features.c > +++ b/target/s390x/gen-features.c > @@ -754,6 +754,7 @@ static uint16_t qemu_MAX[] = { > S390_FEAT_MSA_EXT_5, > S390_FEAT_KIMD_SHA_512, > S390_FEAT_KLMD_SHA_512, > + S390_FEAT_PRNO_TRNG, > }; > > /****** END FEATURE DEFS ******/ > diff --git a/target/s390x/tcg/crypto_helper.c b/target/s390x/tcg/crypto_helper.c > index 02073ec70b..0daa9a2dd9 100644 > --- a/target/s390x/tcg/crypto_helper.c > +++ b/target/s390x/tcg/crypto_helper.c > @@ -14,6 +14,7 @@ > > #include "qemu/osdep.h" > #include "qemu/main-loop.h" > +#include "qemu/guest-random.h" > #include "s390x-internal.h" > #include "tcg_s390x.h" > #include "exec/helper-proto.h" > @@ -173,6 +174,31 @@ static int klmd_sha512(CPUS390XState *env, uintptr_t ra, uint64_t parameter_bloc > return 0; > } > > +static void fill_buf_random(CPUS390XState *env, uintptr_t ra, > + uint64_t *buf_reg, uint64_t *len_reg) > +{ > + uint8_t tmp[256]; > + uint64_t len = *len_reg; > + int buf_reg_len = 64; > + > + if (!(env->psw.mask & PSW_MASK_64)) { > + len = (uint32_t)len; > + buf_reg_len = (env->psw.mask & PSW_MASK_32) ? 32 : 24; > + } > + > + while (len) { > + size_t block = MIN(len, sizeof(tmp)); > + > + qemu_guest_getrandom_nofail(tmp, block); > + for (size_t i = 0; i < block; ++i) { > + cpu_stb_data_ra(env, wrap_address(env, *buf_reg), tmp[i], ra); > + *buf_reg = deposit64(*buf_reg, 0, buf_reg_len, *buf_reg + 1); > + --*len_reg; > + } > + len -= block; > + } > +} > + > uint32_t HELPER(msa)(CPUS390XState *env, uint32_t r1, uint32_t r2, uint32_t r3, > uint32_t type) > { > @@ -215,6 +241,10 @@ uint32_t HELPER(msa)(CPUS390XState *env, uint32_t r1, uint32_t r2, uint32_t r3, > return klmd_sha512(env, ra, env->regs[1], &env->regs[r2], &env->regs[r2 + 1]); > } > break; > + case 114: /* CPACF_PRNO_TRNG */ > + fill_buf_random(env, ra, &env->regs[r1], &env->regs[r1 + 1]); > + fill_buf_random(env, ra, &env->regs[r2], &env->regs[r2 + 1]); > + break; Thanks, patch looks fine to me! (if we ever have another instruction that uses fc 114, we might want to check "type" here, too, but that can also be added later, of course) Thomas
On 21/09/2022 12.07, Jason A. Donenfeld wrote: > In order for hosts running inside of TCG to initialize the kernel's > random number generator, we should support the PRNO_TRNG instruction, > backed in the usual way with the qemu_guest_getrandom helper. This is > confirmed working on Linux 5.19. > > Cc: Thomas Huth <thuth@redhat.com> > Cc: David Hildenbrand <david@redhat.com> > Cc: Christian Borntraeger <borntraeger@linux.ibm.com> > Cc: Richard Henderson <richard.henderson@linaro.org> > Cc: Cornelia Huck <cohuck@redhat.com> > Cc: Harald Freudenberger <freude@linux.ibm.com> > Cc: Holger Dengler <dengler@linux.ibm.com> > Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com> > --- > target/s390x/gen-features.c | 1 + > target/s390x/tcg/crypto_helper.c | 30 ++++++++++++++++++++++++++++++ > 2 files changed, 31 insertions(+) Seems like this is even working fine with older Linux kernels ... your patch accidentally broke test_s390x_devices in tests/avocado/machine_s390_ccw_virtio.py: This test adds two virtio-rng devices to the guest, then ejects them to see whether /dev/hwrng will be gone ... which does not happen anymore with the prno-trng feature enabled :-) I'm going to squash this one-liner to fix this issue: diff a/tests/avocado/machine_s390_ccw_virtio.py b/tests/avocado/machine_s390_ccw_virtio.py --- a/tests/avocado/machine_s390_ccw_virtio.py +++ b/tests/avocado/machine_s390_ccw_virtio.py @@ -66,6 +66,7 @@ def test_s390x_devices(self): '-kernel', kernel_path, '-initrd', initrd_path, '-append', kernel_command_line, + '-cpu', 'max,prno-trng=off', '-device', 'virtio-net-ccw,devno=fe.1.1111', '-device', 'virtio-rng-ccw,devno=fe.2.0000,max_revision=0,id=rn1', Thomas
On Mon, Sep 26, 2022 at 5:11 PM Thomas Huth <thuth@redhat.com> wrote: > Seems like this is even working fine with older Linux kernels ... Oh good! your patch accidentally broke test_s390x_devices in tests/avocado/machine_s390_ccw_virtio.py: This test adds two virtio-rng devices to the guest, then ejects them to see whether /dev/hwrng will be gone ... which does not happen anymore with the prno-trng feature enabled :-) > > I'm going to squash this one-liner to fix this issue: Seems reasonable. Thanks. Jason
diff --git a/target/s390x/gen-features.c b/target/s390x/gen-features.c index 14a7f2ae90..aaade67574 100644 --- a/target/s390x/gen-features.c +++ b/target/s390x/gen-features.c @@ -754,6 +754,7 @@ static uint16_t qemu_MAX[] = { S390_FEAT_MSA_EXT_5, S390_FEAT_KIMD_SHA_512, S390_FEAT_KLMD_SHA_512, + S390_FEAT_PRNO_TRNG, }; /****** END FEATURE DEFS ******/ diff --git a/target/s390x/tcg/crypto_helper.c b/target/s390x/tcg/crypto_helper.c index 02073ec70b..0daa9a2dd9 100644 --- a/target/s390x/tcg/crypto_helper.c +++ b/target/s390x/tcg/crypto_helper.c @@ -14,6 +14,7 @@ #include "qemu/osdep.h" #include "qemu/main-loop.h" +#include "qemu/guest-random.h" #include "s390x-internal.h" #include "tcg_s390x.h" #include "exec/helper-proto.h" @@ -173,6 +174,31 @@ static int klmd_sha512(CPUS390XState *env, uintptr_t ra, uint64_t parameter_bloc return 0; } +static void fill_buf_random(CPUS390XState *env, uintptr_t ra, + uint64_t *buf_reg, uint64_t *len_reg) +{ + uint8_t tmp[256]; + uint64_t len = *len_reg; + int buf_reg_len = 64; + + if (!(env->psw.mask & PSW_MASK_64)) { + len = (uint32_t)len; + buf_reg_len = (env->psw.mask & PSW_MASK_32) ? 32 : 24; + } + + while (len) { + size_t block = MIN(len, sizeof(tmp)); + + qemu_guest_getrandom_nofail(tmp, block); + for (size_t i = 0; i < block; ++i) { + cpu_stb_data_ra(env, wrap_address(env, *buf_reg), tmp[i], ra); + *buf_reg = deposit64(*buf_reg, 0, buf_reg_len, *buf_reg + 1); + --*len_reg; + } + len -= block; + } +} + uint32_t HELPER(msa)(CPUS390XState *env, uint32_t r1, uint32_t r2, uint32_t r3, uint32_t type) { @@ -215,6 +241,10 @@ uint32_t HELPER(msa)(CPUS390XState *env, uint32_t r1, uint32_t r2, uint32_t r3, return klmd_sha512(env, ra, env->regs[1], &env->regs[r2], &env->regs[r2 + 1]); } break; + case 114: /* CPACF_PRNO_TRNG */ + fill_buf_random(env, ra, &env->regs[r1], &env->regs[r1 + 1]); + fill_buf_random(env, ra, &env->regs[r2], &env->regs[r2 + 1]); + break; default: /* we don't implement any other subfunction yet */ g_assert_not_reached();
In order for hosts running inside of TCG to initialize the kernel's random number generator, we should support the PRNO_TRNG instruction, backed in the usual way with the qemu_guest_getrandom helper. This is confirmed working on Linux 5.19. Cc: Thomas Huth <thuth@redhat.com> Cc: David Hildenbrand <david@redhat.com> Cc: Christian Borntraeger <borntraeger@linux.ibm.com> Cc: Richard Henderson <richard.henderson@linaro.org> Cc: Cornelia Huck <cohuck@redhat.com> Cc: Harald Freudenberger <freude@linux.ibm.com> Cc: Holger Dengler <dengler@linux.ibm.com> Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com> --- target/s390x/gen-features.c | 1 + target/s390x/tcg/crypto_helper.c | 30 ++++++++++++++++++++++++++++++ 2 files changed, 31 insertions(+)