MIPS: KVM: Add MSA exception handling

Add guest exception handling for MIPS SIMD Architecture (MSA) floating
point exceptions and MSA disabled exceptions.

MSA floating point exceptions from the guest need passing to the guest
kernel, so for these a guest MSAFPE is emulated.

MSA disabled exceptions are normally handled by passing a reserved
instruction exception to the guest (because no guest MSA was supported),
but the hypervisor can now handle them if the guest has MSA by passing
an MSA disabled exception to the guest, or if the guest has MSA enabled
by transparently restoring the guest MSA context and enabling MSA and
the FPU.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Paul Burton <paul.burton@imgtec.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Gleb Natapov <gleb@kernel.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org

1 files changed, 10 insertions, 0 deletions

diff --git a/arch/mips/kvm/mips.c b/arch/mips/kvm/mips.c
index a17f21015a0b..e02c7e5a12ff 100644
--- a/arch/mips/kvm/mips.c
+++ b/arch/mips/kvm/mips.c
@@ -50,7 +50,9 @@ struct kvm_stats_debugfs_item debugfs_entries[] = {
         { "resvd_inst",   VCPU_STAT(resvd_inst_exits),   KVM_STAT_VCPU },
         { "break_inst",   VCPU_STAT(break_inst_exits),   KVM_STAT_VCPU },
         { "trap_inst",    VCPU_STAT(trap_inst_exits),    KVM_STAT_VCPU },
+        { "msa_fpe",      VCPU_STAT(msa_fpe_exits),      KVM_STAT_VCPU },
         { "fpe",          VCPU_STAT(fpe_exits),          KVM_STAT_VCPU },
+        { "msa_disabled", VCPU_STAT(msa_disabled_exits), KVM_STAT_VCPU },
         { "flush_dcache", VCPU_STAT(flush_dcache_exits), KVM_STAT_VCPU },
         { "halt_successful_poll", VCPU_STAT(halt_successful_poll), KVM_STAT_VCPU },
         { "halt_wakeup",  VCPU_STAT(halt_wakeup),        KVM_STAT_VCPU },
@@ -1256,6 +1258,12 @@ int kvm_mips_handle_exit(struct kvm_run *run, struct kvm_vcpu *vcpu)
                 ret = kvm_mips_callbacks->handle_trap(vcpu);
                 break;
 
+        case T_MSAFPE:
+                ++vcpu->stat.msa_fpe_exits;
+                trace_kvm_exit(vcpu, MSA_FPE_EXITS);
+                ret = kvm_mips_callbacks->handle_msa_fpe(vcpu);
+                break;
+
         case T_FPE:
                 ++vcpu->stat.fpe_exits;
                 trace_kvm_exit(vcpu, FPE_EXITS);
@@ -1263,6 +1271,8 @@ int kvm_mips_handle_exit(struct kvm_run *run, struct kvm_vcpu *vcpu)
                 break;
 
         case T_MSADIS:
+                ++vcpu->stat.msa_disabled_exits;
+                trace_kvm_exit(vcpu, MSA_DISABLED_EXITS);
                 ret = kvm_mips_callbacks->handle_msa_disabled(vcpu);
                 break;