In the context of replacing kvmppc_ld() function calls with a version of
kvmppc_get_last_inst() which allow to fail, Alex Graf suggested this:
"If we get EMULATE_AGAIN, we just have to make sure we go back into the guest.
No need to inject an ISI into the guest - it'll do that all by itself.
With an error returning kvmppc_get_last_inst we can just use completely
get rid of kvmppc_read_inst() and only use kvmppc_get_last_inst() instead."
As a intermediate step get rid of kvmppc_read_inst() and only use kvmppc_ld()
instead.
Signed-off-by: Mihai Caraman <mihai.caraman@xxxxxxxxxxxxx>
---
v5:
- make paired single emulation the unusual
v4:
- new patch
arch/powerpc/kvm/book3s_pr.c | 91 ++++++++++++++++++--------------------------
1 file changed, 37 insertions(+), 54 deletions(-)
diff --git a/arch/powerpc/kvm/book3s_pr.c b/arch/powerpc/kvm/book3s_pr.c
index e40765f..02a983e 100644
--- a/arch/powerpc/kvm/book3s_pr.c
+++ b/arch/powerpc/kvm/book3s_pr.c
@@ -710,42 +710,6 @@ static void kvmppc_giveup_fac(struct kvm_vcpu *vcpu, ulong fac)
#endif
}
-static int kvmppc_read_inst(struct kvm_vcpu *vcpu)
-{
- ulong srr0 = kvmppc_get_pc(vcpu);
- u32 last_inst = kvmppc_get_last_inst(vcpu);
- int ret;
-
- ret = kvmppc_ld(vcpu, &srr0, sizeof(u32), &last_inst, false);
- if (ret == -ENOENT) {
- ulong msr = kvmppc_get_msr(vcpu);
-
- msr = kvmppc_set_field(msr, 33, 33, 1);
- msr = kvmppc_set_field(msr, 34, 36, 0);
- msr = kvmppc_set_field(msr, 42, 47, 0);
- kvmppc_set_msr_fast(vcpu, msr);
- kvmppc_book3s_queue_irqprio(vcpu, BOOK3S_INTERRUPT_INST_STORAGE);
- return EMULATE_AGAIN;
- }
-
- return EMULATE_DONE;
-}
-
-static int kvmppc_check_ext(struct kvm_vcpu *vcpu, unsigned int exit_nr)
-{
-
- /* Need to do paired single emulation? */
- if (!(vcpu->arch.hflags & BOOK3S_HFLAG_PAIRED_SINGLE))
- return EMULATE_DONE;
-
- /* Read out the instruction */
- if (kvmppc_read_inst(vcpu) == EMULATE_DONE)
- /* Need to emulate */
- return EMULATE_FAIL;
-
- return EMULATE_AGAIN;
-}
-
/* Handle external providers (FPU, Altivec, VSX) */
static int kvmppc_handle_ext(struct kvm_vcpu *vcpu, unsigned int exit_nr,
ulong msr)
@@ -1149,31 +1113,49 @@ program_interrupt:
case BOOK3S_INTERRUPT_VSX:
{
int ext_msr = 0;
+ int emul;
+ ulong pc;
+ u32 last_inst;
+
+ if (vcpu->arch.hflags & BOOK3S_HFLAG_PAIRED_SINGLE) {
+ /* Emulate the instruction */
+
+ pc = kvmppc_get_pc(vcpu);
+ last_inst = kvmppc_get_last_inst(vcpu);
+ emul = kvmppc_ld(vcpu, &pc, sizeof(u32), &last_inst,
+ false);
+ if (emul == EMULATE_DONE)
+ goto program_interrupt;
+ else
+ r = RESUME_GUEST;
+ } else {
+ /* Do paired single emulation */
- switch (exit_nr) {
- case BOOK3S_INTERRUPT_FP_UNAVAIL: ext_msr = MSR_FP; break;
- case BOOK3S_INTERRUPT_ALTIVEC: ext_msr = MSR_VEC; break;
- case BOOK3S_INTERRUPT_VSX: ext_msr = MSR_VSX; break;
- }
+ switch (exit_nr) {
+ case BOOK3S_INTERRUPT_FP_UNAVAIL:
+ ext_msr = MSR_FP;
+ break;
+
+ case BOOK3S_INTERRUPT_ALTIVEC:
+ ext_msr = MSR_VEC;
+ break;
+
+ case BOOK3S_INTERRUPT_VSX:
+ ext_msr = MSR_VSX;
+ break;
+ }
- switch (kvmppc_check_ext(vcpu, exit_nr)) {
- case EMULATE_DONE:
- /* everything ok - let's enable the ext */
r = kvmppc_handle_ext(vcpu, exit_nr, ext_msr);
- break;
- case EMULATE_FAIL:
- /* we need to emulate this instruction */
- goto program_interrupt;
- break;
- default:
- /* nothing to worry about - go again */
- break;
}
break;
}
case BOOK3S_INTERRUPT_ALIGNMENT:
- if (kvmppc_read_inst(vcpu) == EMULATE_DONE) {
- u32 last_inst = kvmppc_get_last_inst(vcpu);
+ {
+ ulong pc = kvmppc_get_pc(vcpu);
+ u32 last_inst = kvmppc_get_last_inst(vcpu);
+ int emul = kvmppc_ld(vcpu, &pc, sizeof(u32), &last_inst, false);
+
+ if (emul == EMULATE_DONE) {
u32 dsisr;
u64 dar;
@@ -1187,6 +1169,7 @@ program_interrupt:
}
r = RESUME_GUEST;
break;
+ }
#ifdef CONFIG_PPC_BOOK3S_64
case BOOK3S_INTERRUPT_FAC_UNAVAIL:
kvmppc_handle_fac(vcpu, vcpu->arch.shadow_fscr >> 56);
--
1.7.11.7
--
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