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KVM: PPC: Book3S PR: Add math support for PR KVM HTM

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The math registers will be saved into vcpu->arch.fp/vr and corresponding
vcpu->arch.fp_tm/vr_tm area.

We flush or giveup the math regs into vcpu->arch.fp/vr before saving
transaction. After transaction is restored, the math regs will be loaded
back into regs.

If there is a FP/VEC/VSX unavailable exception during transaction active
state, the math checkpoint content might be incorrect and we need to do
treclaim./load the correct checkpoint val/trechkpt. sequence to retry the
transaction. That will make our solution complicated. To solve this issue,
we always make the hardware guest MSR math bits (shadow_msr) consistent
with the MSR val which guest sees (kvmppc_get_msr()) when guest msr is
with tm enabled. Then all FP/VEC/VSX unavailable exception can be delivered
to guest and guest handles the exception by itself.

Signed-off-by: Simon Guo <wei.guo.simon@gmail.com>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
This commit is contained in:
Simon Guo 2018-05-23 15:01:59 +08:00 committed by Paul Mackerras
parent 8d2e2fc5e0
commit 13989b65eb
1 changed files with 35 additions and 0 deletions
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35
arch/powerpc/kvm/book3s_pr.c
View file

@ -308,6 +308,28 @@ static inline void kvmppc_restore_tm_sprs(struct kvm_vcpu *vcpu)
tm_disable();
}
/* loadup math bits which is enabled at kvmppc_get_msr() but not enabled at
* hardware.
*/
static void kvmppc_handle_lost_math_exts(struct kvm_vcpu *vcpu)
{
ulong exit_nr;
ulong ext_diff = (kvmppc_get_msr(vcpu) & ~vcpu->arch.guest_owned_ext) &
(MSR_FP | MSR_VEC | MSR_VSX);
if (!ext_diff)
return;
if (ext_diff == MSR_FP)
exit_nr = BOOK3S_INTERRUPT_FP_UNAVAIL;
else if (ext_diff == MSR_VEC)
exit_nr = BOOK3S_INTERRUPT_ALTIVEC;
else
exit_nr = BOOK3S_INTERRUPT_VSX;
kvmppc_handle_ext(vcpu, exit_nr, ext_diff);
}
void kvmppc_save_tm_pr(struct kvm_vcpu *vcpu)
{
if (!(MSR_TM_ACTIVE(kvmppc_get_msr(vcpu)))) {
@ -315,6 +337,8 @@ void kvmppc_save_tm_pr(struct kvm_vcpu *vcpu)
return;
}
kvmppc_giveup_ext(vcpu, MSR_VSX);
preempt_disable();
_kvmppc_save_tm_pr(vcpu, mfmsr());
preempt_enable();
@ -324,12 +348,18 @@ void kvmppc_restore_tm_pr(struct kvm_vcpu *vcpu)
{
if (!MSR_TM_ACTIVE(kvmppc_get_msr(vcpu))) {
kvmppc_restore_tm_sprs(vcpu);
if (kvmppc_get_msr(vcpu) & MSR_TM)
kvmppc_handle_lost_math_exts(vcpu);
return;
}
preempt_disable();
_kvmppc_restore_tm_pr(vcpu, kvmppc_get_msr(vcpu));
preempt_enable();
if (kvmppc_get_msr(vcpu) & MSR_TM)
kvmppc_handle_lost_math_exts(vcpu);
}
#endif
@ -468,6 +498,11 @@ static void kvmppc_set_msr_pr(struct kvm_vcpu *vcpu, u64 msr)
/* Preload FPU if it's enabled */
if (kvmppc_get_msr(vcpu) & MSR_FP)
kvmppc_handle_ext(vcpu, BOOK3S_INTERRUPT_FP_UNAVAIL, MSR_FP);
#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
if (kvmppc_get_msr(vcpu) & MSR_TM)
kvmppc_handle_lost_math_exts(vcpu);
#endif
}
void kvmppc_set_pvr_pr(struct kvm_vcpu *vcpu, u32 pvr)