diff --git a/target/arm/machine.c b/target/arm/machine.c index 0a722ca7e7..8c820955d9 100644 --- a/target/arm/machine.c +++ b/target/arm/machine.c @@ -18,6 +18,34 @@ static bool vfp_needed(void *opaque) : cpu_isar_feature(aa32_vfp_simd, cpu)); } +static bool vfp_fpcr_fpsr_needed(void *opaque) +{ + /* + * If either the FPCR or the FPSR include set bits that are not + * visible in the AArch32 FPSCR view of floating point control/status + * then we must send the FPCR and FPSR as two separate fields in the + * cpu/vfp/fpcr_fpsr subsection, and we will send a 0 for the old + * FPSCR field in cpu/vfp. + * + * If all the set bits are representable in an AArch32 FPSCR then we + * send that value as the cpu/vfp FPSCR field, and don't send the + * cpu/vfp/fpcr_fpsr subsection. + * + * On incoming migration, if the cpu/vfp FPSCR field is non-zero we + * use it, and if the fpcr_fpsr subsection is present we use that. + * (The subsection will never be present with a non-zero FPSCR field, + * and if FPSCR is zero and the subsection is not present that means + * that FPSCR/FPSR/FPCR are zero.) + * + * This preserves migration compatibility with older QEMU versions, + * in both directions. + */ + ARMCPU *cpu = opaque; + CPUARMState *env = &cpu->env; + + return (vfp_get_fpcr(env) & ~FPCR_MASK) || (vfp_get_fpsr(env) & ~FPSR_MASK); +} + static int get_fpscr(QEMUFile *f, void *opaque, size_t size, const VMStateField *field) { @@ -25,7 +53,10 @@ static int get_fpscr(QEMUFile *f, void *opaque, size_t size, CPUARMState *env = &cpu->env; uint32_t val = qemu_get_be32(f); - vfp_set_fpscr(env, val); + if (val) { + /* 0 means we might have the data in the fpcr_fpsr subsection */ + vfp_set_fpscr(env, val); + } return 0; } @@ -34,8 +65,9 @@ static int put_fpscr(QEMUFile *f, void *opaque, size_t size, { ARMCPU *cpu = opaque; CPUARMState *env = &cpu->env; + uint32_t fpscr = vfp_fpcr_fpsr_needed(opaque) ? 0 : vfp_get_fpscr(env); - qemu_put_be32(f, vfp_get_fpscr(env)); + qemu_put_be32(f, fpscr); return 0; } @@ -45,6 +77,86 @@ static const VMStateInfo vmstate_fpscr = { .put = put_fpscr, }; +static int get_fpcr(QEMUFile *f, void *opaque, size_t size, + const VMStateField *field) +{ + ARMCPU *cpu = opaque; + CPUARMState *env = &cpu->env; + uint64_t val = qemu_get_be64(f); + + vfp_set_fpcr(env, val); + return 0; +} + +static int put_fpcr(QEMUFile *f, void *opaque, size_t size, + const VMStateField *field, JSONWriter *vmdesc) +{ + ARMCPU *cpu = opaque; + CPUARMState *env = &cpu->env; + + qemu_put_be64(f, vfp_get_fpcr(env)); + return 0; +} + +static const VMStateInfo vmstate_fpcr = { + .name = "fpcr", + .get = get_fpcr, + .put = put_fpcr, +}; + +static int get_fpsr(QEMUFile *f, void *opaque, size_t size, + const VMStateField *field) +{ + ARMCPU *cpu = opaque; + CPUARMState *env = &cpu->env; + uint64_t val = qemu_get_be64(f); + + vfp_set_fpsr(env, val); + return 0; +} + +static int put_fpsr(QEMUFile *f, void *opaque, size_t size, + const VMStateField *field, JSONWriter *vmdesc) +{ + ARMCPU *cpu = opaque; + CPUARMState *env = &cpu->env; + + qemu_put_be64(f, vfp_get_fpsr(env)); + return 0; +} + +static const VMStateInfo vmstate_fpsr = { + .name = "fpsr", + .get = get_fpsr, + .put = put_fpsr, +}; + +static const VMStateDescription vmstate_vfp_fpcr_fpsr = { + .name = "cpu/vfp/fpcr_fpsr", + .version_id = 1, + .minimum_version_id = 1, + .needed = vfp_fpcr_fpsr_needed, + .fields = (const VMStateField[]) { + { + .name = "fpcr", + .version_id = 0, + .size = sizeof(uint64_t), + .info = &vmstate_fpcr, + .flags = VMS_SINGLE, + .offset = 0, + }, + { + .name = "fpsr", + .version_id = 0, + .size = sizeof(uint64_t), + .info = &vmstate_fpsr, + .flags = VMS_SINGLE, + .offset = 0, + }, + VMSTATE_END_OF_LIST() + }, +}; + static const VMStateDescription vmstate_vfp = { .name = "cpu/vfp", .version_id = 3, @@ -100,6 +212,10 @@ static const VMStateDescription vmstate_vfp = { .offset = 0, }, VMSTATE_END_OF_LIST() + }, + .subsections = (const VMStateDescription * const []) { + &vmstate_vfp_fpcr_fpsr, + NULL } }; @@ -784,6 +900,20 @@ static int cpu_pre_load(void *opaque) ARMCPU *cpu = opaque; CPUARMState *env = &cpu->env; + /* + * In an inbound migration where on the source FPSCR/FPSR/FPCR are 0, + * there will be no fpcr_fpsr subsection so we won't call vfp_set_fpcr() + * and vfp_set_fpsr() from get_fpcr() and get_fpsr(); also the get_fpscr() + * function will not call vfp_set_fpscr() because it will see a 0 in the + * inbound data. Ensure that in this case we have a correctly set up + * zero FPSCR/FPCR/FPSR. + * + * This is not strictly needed because FPSCR is zero out of reset, but + * it avoids the possibility of future confusing migration bugs if some + * future architecture change makes the reset value non-zero. + */ + vfp_set_fpscr(env, 0); + /* * Pre-initialize irq_line_state to a value that's never valid as * real data, so cpu_post_load() can tell whether we've seen the