On 5/12/21 9:08 AM, Bruno Larsen (billionai) wrote:
diff --git a/target/ppc/kvm.c b/target/ppc/kvm.c
index 104a308abb..a8a720eb48 100644
--- a/target/ppc/kvm.c
+++ b/target/ppc/kvm.c
@@ -2947,3 +2947,17 @@ bool kvm_arch_cpu_check_are_resettable(void)
{
return true;
}
+
+void kvmppc_store_fpscr(CPUPPCState *env, uint64_t arg, uint32_t mask)
+{
+ CPUState *cs = env_cpu(env);
+ struct kvm_one_reg reg;
+ int ret;
+ reg.id = KVM_REG_PPC_FPSCR;
+ reg.addr = (uintptr_t) &env->fpscr;
+ ret = kvm_vcpu_ioctl(cs, KVM_SET_ONE_REG, ®);
+ if (ret < 0)
+ {
+ fprintf(stderr, "Unable to set FPSCR to KVM: %s", strerror(errno));
+ }
+}
This is all unnecessary. All you need to do is store to env->fpscr and the
value will be synced back with kvm_put_fp.
I'll note that some of the trouble you may be having with extracting
helper_store_fpscr to a ppc_store_fpscr function is due to an existing bug in
the tcg code:
Storing to fpscr should *never* raise an exception -- see MTFSF, MTFSB0,
MTFSB1. Thus the mucking about with cs->exception_index and env->error_code
is incorrect.
In addition, the masking is being done weirdly and could use a complete
overhaul.
This could all be rewritten as
-- %< -- cpu.h
/* Invalid operation exception summary */
- #define fpscr_ix ((env->fpscr) & ((1 << FPSCR_VXSNAN) ...
+ #define FPSCR_IX ((1 << FPSCR_VXSNAN) | ...)
-- %< -- cpu.c
// move fpscr_set_rounding_mode here
void ppc_store_fpscr(CPUPPCState *env, target_ulong val)
{
/* Recompute exception summary state. */
val &= ~(FP_VX | FP_FEX);
if (val & FPSCR_IX) {
val |= FP_VX;
}
if ((val >> FPSCR_XX) & (val >> FPSCR_XE) & 0x1f) {
val |= FP_FEX;
}
env->fpscr = val;
if (tcg_enabled()) {
fpscr_set_rounding_mode(env);
}
}
-- %< -- fpu_helper.c
void helper_store_fpscr(CPUPPCState *env, target_ulong val,
uint32_t nibbles)
{
target_ulong mask = 0;
/* TODO: Push this expansion back to translation time. */
for (int i = 0; i < sizeof(target_ulong) * 2; ++i) {
if (nibbles & (1 << i)) {
mask |= (target_ulong)0xf << (4 * i);
}
}
val = (val & mask) | (env->fpscr & ~mask);
ppc_store_fpscr(env, val);
}
void helper_fpscr_clrbit(CPUPPCState *env, uint32_t bit)
{
uint32_t mask = 1u << bit;
if (env->fpscr & mask) {
ppc_store_fpscr(env, env->fpscr & ~mask);
}
}
void helper_fpscr_setbit(CPUPPCState *env, uint32_t bit)
{
uint32_t mask = 1u << bit;
if (!(env->fpscr & mask)) {
ppc_store_fpscr(env, env->fpscr | mask);
}
}
There are a couple of other uses of fpscr_set_rounding_mode, where the
softfloat value is changed temporarily (do_fri, VSX_ROUND). These should
simply save the previous softfloat value (using get_float_rounding_mode)
around the operation instead of re-computing from fpscr.
Which leaves us with exactly one use of fpscr_set_rounding_mode, which can
then be moved to cpu.c next to ppc_store_fpscr.
r~