Message ID | 20170921213052.1765-1-david@redhat.com |
---|---|
State | New |
Headers | show |
Series | [v1] s390x/kvm: fix and cleanup storing CPU status | expand |
On 09/21/2017 04:30 PM, David Hildenbrand wrote: > +struct sigp_save_area { > + uint64_t fprs[16]; /* 0x0000 */ > + uint64_t grs[16]; /* 0x0080 */ > + PSW psw; /* 0x0100 */ > + uint8_t pad_0x0110[0x0118 - 0x0110]; /* 0x0110 */ > + uint32_t prefix; /* 0x0118 */ > + uint32_t fpc; /* 0x011c */ > + uint8_t pad_0x0120[0x0124 - 0x0120]; /* 0x0120 */ > + uint32_t todpr; /* 0x0124 */ > + uint64_t cputm; /* 0x0128 */ > + uint64_t ckc; /* 0x0130 */ > + uint8_t pad_0x0138[0x0140 - 0x0138]; /* 0x0138 */ > + uint32_t ars[16]; /* 0x0140 */ > + uint64_t crs[16]; /* 0x0384 */ > +} QEMU_PACKED; I don't believe you need to use QEMU_PACKED. Unless the "addr" that's passed in can really be arbitrary? (If so, the memory returned by cpu_physical_memory_map will be unaligned and so we do need the PACKED to force the compiler to generate unaligned stores into the structure.) > QEMU_BUILD_BUG_ON(sizeof(*sa) != 512); Put this right next to the structure? r~
On 22.09.2017 15:12, Richard Henderson wrote: > On 09/21/2017 04:30 PM, David Hildenbrand wrote: >> +struct sigp_save_area { >> + uint64_t fprs[16]; /* 0x0000 */ >> + uint64_t grs[16]; /* 0x0080 */ >> + PSW psw; /* 0x0100 */ >> + uint8_t pad_0x0110[0x0118 - 0x0110]; /* 0x0110 */ >> + uint32_t prefix; /* 0x0118 */ >> + uint32_t fpc; /* 0x011c */ >> + uint8_t pad_0x0120[0x0124 - 0x0120]; /* 0x0120 */ >> + uint32_t todpr; /* 0x0124 */ >> + uint64_t cputm; /* 0x0128 */ >> + uint64_t ckc; /* 0x0130 */ >> + uint8_t pad_0x0138[0x0140 - 0x0138]; /* 0x0138 */ >> + uint32_t ars[16]; /* 0x0140 */ >> + uint64_t crs[16]; /* 0x0384 */ >> +} QEMU_PACKED; > > I don't believe you need to use QEMU_PACKED. Unless the "addr" that's passed > in can really be arbitrary? (If so, the memory returned by > cpu_physical_memory_map will be unaligned and so we do need the PACKED to force > the compiler to generate unaligned stores into the structure.) The address is either 0x1200 or it is masked with 0x7ffffe00u. So most probably this should be fine without QEMU_PACKED, right? > >> QEMU_BUILD_BUG_ON(sizeof(*sa) != 512); > > Put this right next to the structure? > Wasn't aware that this can be moved outside of a function. Thanks! Thanks! > > r~ >
On 09/21/2017 11:30 PM, David Hildenbrand wrote: > env->psa is a 64bit value, while we copy 4 bytes into the save area, > resulting always in 0 getting stored. > > Let's try to reduce such errors by using a proper structure. While at > it, use correct cpu->be conversion (and get_psw_mask()), as we will be > reusing this code for TCG soon. Interesting, I would have expected it to break kdump, but this did work. So it probably works differently. Anyway this looks sane, no obvious bug. > > Signed-off-by: David Hildenbrand <david@redhat.com> > --- > > Found with my fancy SIGP kvm-unit-tests I am currently working on. And > looks like there is even more ... stay tuned :) > > target/s390x/kvm.c | 63 +++++++++++++++++++++++++++++++++++++----------------- > 1 file changed, 43 insertions(+), 20 deletions(-) > > diff --git a/target/s390x/kvm.c b/target/s390x/kvm.c > index 720cb1d833..21c22f48b9 100644 > --- a/target/s390x/kvm.c > +++ b/target/s390x/kvm.c > @@ -1548,22 +1548,38 @@ static int do_store_adtl_status(S390CPU *cpu, hwaddr addr, hwaddr len) > return 0; > } > > +struct sigp_save_area { > + uint64_t fprs[16]; /* 0x0000 */ > + uint64_t grs[16]; /* 0x0080 */ > + PSW psw; /* 0x0100 */ > + uint8_t pad_0x0110[0x0118 - 0x0110]; /* 0x0110 */ > + uint32_t prefix; /* 0x0118 */ > + uint32_t fpc; /* 0x011c */ > + uint8_t pad_0x0120[0x0124 - 0x0120]; /* 0x0120 */ > + uint32_t todpr; /* 0x0124 */ > + uint64_t cputm; /* 0x0128 */ > + uint64_t ckc; /* 0x0130 */ > + uint8_t pad_0x0138[0x0140 - 0x0138]; /* 0x0138 */ > + uint32_t ars[16]; /* 0x0140 */ > + uint64_t crs[16]; /* 0x0384 */ > +} QEMU_PACKED; > + > #define KVM_S390_STORE_STATUS_DEF_ADDR offsetof(LowCore, floating_pt_save_area) > -#define SAVE_AREA_SIZE 512 > static int kvm_s390_store_status(S390CPU *cpu, hwaddr addr, bool store_arch) > { > static const uint8_t ar_id = 1; > - uint64_t ckc = cpu->env.ckc >> 8; > - void *mem; > + struct sigp_save_area *sa; > + hwaddr len = sizeof(*sa); > int i; > - hwaddr len = SAVE_AREA_SIZE; > > - mem = cpu_physical_memory_map(addr, &len, 1); > - if (!mem) { > + QEMU_BUILD_BUG_ON(sizeof(*sa) != 512); > + > + sa = cpu_physical_memory_map(addr, &len, 1); > + if (!sa) { > return -EFAULT; > } > - if (len != SAVE_AREA_SIZE) { > - cpu_physical_memory_unmap(mem, len, 1, 0); > + if (len != sizeof(*sa)) { > + cpu_physical_memory_unmap(sa, len, 1, 0); > return -EFAULT; > } > > @@ -1571,19 +1587,26 @@ static int kvm_s390_store_status(S390CPU *cpu, hwaddr addr, bool store_arch) > cpu_physical_memory_write(offsetof(LowCore, ar_access_id), &ar_id, 1); > } > for (i = 0; i < 16; ++i) { > - *((uint64_t *)mem + i) = get_freg(&cpu->env, i)->ll; > - } > - memcpy(mem + 128, &cpu->env.regs, 128); > - memcpy(mem + 256, &cpu->env.psw, 16); > - memcpy(mem + 280, &cpu->env.psa, 4); > - memcpy(mem + 284, &cpu->env.fpc, 4); > - memcpy(mem + 292, &cpu->env.todpr, 4); > - memcpy(mem + 296, &cpu->env.cputm, 8); > - memcpy(mem + 304, &ckc, 8); > - memcpy(mem + 320, &cpu->env.aregs, 64); > - memcpy(mem + 384, &cpu->env.cregs, 128); > + sa->fprs[i] = cpu_to_be64(get_freg(&cpu->env, i)->ll); > + } > + for (i = 0; i < 16; ++i) { > + sa->grs[i] = cpu_to_be64(cpu->env.regs[i]); > + } > + sa->psw.addr = cpu_to_be64(cpu->env.psw.addr); > + sa->psw.mask = cpu_to_be64(get_psw_mask(&cpu->env)); > + sa->prefix = cpu_to_be32(cpu->env.psa); > + sa->fpc = cpu_to_be32(cpu->env.fpc); > + sa->todpr = cpu_to_be32(cpu->env.todpr); > + sa->cputm = cpu_to_be64(cpu->env.cputm); > + sa->ckc = cpu_to_be64(cpu->env.ckc >> 8); > + for (i = 0; i < 16; ++i) { > + sa->ars[i] = cpu_to_be32(cpu->env.aregs[i]); > + } > + for (i = 0; i < 16; ++i) { > + sa->ars[i] = cpu_to_be64(cpu->env.cregs[i]); > + } > > - cpu_physical_memory_unmap(mem, len, 1, len); > + cpu_physical_memory_unmap(sa, len, 1, len); > > return 0; > } >
On 09/22/2017 08:18 AM, David Hildenbrand wrote: > On 22.09.2017 15:12, Richard Henderson wrote: >> I don't believe you need to use QEMU_PACKED. Unless the "addr" that's passed >> in can really be arbitrary? (If so, the memory returned by >> cpu_physical_memory_map will be unaligned and so we do need the PACKED to force >> the compiler to generate unaligned stores into the structure.) > > The address is either 0x1200 or it is masked with 0x7ffffe00u. > > So most probably this should be fine without QEMU_PACKED, right? Yes. r~
diff --git a/target/s390x/kvm.c b/target/s390x/kvm.c index 720cb1d833..21c22f48b9 100644 --- a/target/s390x/kvm.c +++ b/target/s390x/kvm.c @@ -1548,22 +1548,38 @@ static int do_store_adtl_status(S390CPU *cpu, hwaddr addr, hwaddr len) return 0; } +struct sigp_save_area { + uint64_t fprs[16]; /* 0x0000 */ + uint64_t grs[16]; /* 0x0080 */ + PSW psw; /* 0x0100 */ + uint8_t pad_0x0110[0x0118 - 0x0110]; /* 0x0110 */ + uint32_t prefix; /* 0x0118 */ + uint32_t fpc; /* 0x011c */ + uint8_t pad_0x0120[0x0124 - 0x0120]; /* 0x0120 */ + uint32_t todpr; /* 0x0124 */ + uint64_t cputm; /* 0x0128 */ + uint64_t ckc; /* 0x0130 */ + uint8_t pad_0x0138[0x0140 - 0x0138]; /* 0x0138 */ + uint32_t ars[16]; /* 0x0140 */ + uint64_t crs[16]; /* 0x0384 */ +} QEMU_PACKED; + #define KVM_S390_STORE_STATUS_DEF_ADDR offsetof(LowCore, floating_pt_save_area) -#define SAVE_AREA_SIZE 512 static int kvm_s390_store_status(S390CPU *cpu, hwaddr addr, bool store_arch) { static const uint8_t ar_id = 1; - uint64_t ckc = cpu->env.ckc >> 8; - void *mem; + struct sigp_save_area *sa; + hwaddr len = sizeof(*sa); int i; - hwaddr len = SAVE_AREA_SIZE; - mem = cpu_physical_memory_map(addr, &len, 1); - if (!mem) { + QEMU_BUILD_BUG_ON(sizeof(*sa) != 512); + + sa = cpu_physical_memory_map(addr, &len, 1); + if (!sa) { return -EFAULT; } - if (len != SAVE_AREA_SIZE) { - cpu_physical_memory_unmap(mem, len, 1, 0); + if (len != sizeof(*sa)) { + cpu_physical_memory_unmap(sa, len, 1, 0); return -EFAULT; } @@ -1571,19 +1587,26 @@ static int kvm_s390_store_status(S390CPU *cpu, hwaddr addr, bool store_arch) cpu_physical_memory_write(offsetof(LowCore, ar_access_id), &ar_id, 1); } for (i = 0; i < 16; ++i) { - *((uint64_t *)mem + i) = get_freg(&cpu->env, i)->ll; - } - memcpy(mem + 128, &cpu->env.regs, 128); - memcpy(mem + 256, &cpu->env.psw, 16); - memcpy(mem + 280, &cpu->env.psa, 4); - memcpy(mem + 284, &cpu->env.fpc, 4); - memcpy(mem + 292, &cpu->env.todpr, 4); - memcpy(mem + 296, &cpu->env.cputm, 8); - memcpy(mem + 304, &ckc, 8); - memcpy(mem + 320, &cpu->env.aregs, 64); - memcpy(mem + 384, &cpu->env.cregs, 128); + sa->fprs[i] = cpu_to_be64(get_freg(&cpu->env, i)->ll); + } + for (i = 0; i < 16; ++i) { + sa->grs[i] = cpu_to_be64(cpu->env.regs[i]); + } + sa->psw.addr = cpu_to_be64(cpu->env.psw.addr); + sa->psw.mask = cpu_to_be64(get_psw_mask(&cpu->env)); + sa->prefix = cpu_to_be32(cpu->env.psa); + sa->fpc = cpu_to_be32(cpu->env.fpc); + sa->todpr = cpu_to_be32(cpu->env.todpr); + sa->cputm = cpu_to_be64(cpu->env.cputm); + sa->ckc = cpu_to_be64(cpu->env.ckc >> 8); + for (i = 0; i < 16; ++i) { + sa->ars[i] = cpu_to_be32(cpu->env.aregs[i]); + } + for (i = 0; i < 16; ++i) { + sa->ars[i] = cpu_to_be64(cpu->env.cregs[i]); + } - cpu_physical_memory_unmap(mem, len, 1, len); + cpu_physical_memory_unmap(sa, len, 1, len); return 0; }
env->psa is a 64bit value, while we copy 4 bytes into the save area, resulting always in 0 getting stored. Let's try to reduce such errors by using a proper structure. While at it, use correct cpu->be conversion (and get_psw_mask()), as we will be reusing this code for TCG soon. Signed-off-by: David Hildenbrand <david@redhat.com> --- Found with my fancy SIGP kvm-unit-tests I am currently working on. And looks like there is even more ... stay tuned :) target/s390x/kvm.c | 63 +++++++++++++++++++++++++++++++++++++----------------- 1 file changed, 43 insertions(+), 20 deletions(-)