KVM: PPC: Book3S HV P9: Use Linux SPR save/restore to manage some host SPRs
Linux implements SPR save/restore including storage space for registers
in the task struct for process context switching. Make use of this
similarly to the way we make use of the context switching fp/vec save
restore.
This improves code reuse, allows some stack space to be saved, and helps
with avoiding VRSAVE updates if they are not required.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20211123095231.1036501-39-npiggin@gmail.com
diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
index 198f6d9..7d48aa8 100644
--- a/arch/powerpc/kvm/book3s_hv.c
+++ b/arch/powerpc/kvm/book3s_hv.c
@@ -4566,9 +4566,6 @@ static int kvmppc_vcpu_run_hv(struct kvm_vcpu *vcpu)
struct kvm_run *run = vcpu->run;
int r;
int srcu_idx;
- unsigned long ebb_regs[3] = {}; /* shut up GCC */
- unsigned long user_tar = 0;
- unsigned int user_vrsave;
struct kvm *kvm;
unsigned long msr;
@@ -4629,14 +4626,7 @@ static int kvmppc_vcpu_run_hv(struct kvm_vcpu *vcpu)
kvmppc_save_user_regs();
- /* Save userspace EBB and other register values */
- if (cpu_has_feature(CPU_FTR_ARCH_207S)) {
- ebb_regs[0] = mfspr(SPRN_EBBHR);
- ebb_regs[1] = mfspr(SPRN_EBBRR);
- ebb_regs[2] = mfspr(SPRN_BESCR);
- user_tar = mfspr(SPRN_TAR);
- }
- user_vrsave = mfspr(SPRN_VRSAVE);
+ kvmppc_save_current_sprs();
vcpu->arch.waitp = &vcpu->arch.vcore->wait;
vcpu->arch.pgdir = kvm->mm->pgd;
@@ -4677,15 +4667,6 @@ static int kvmppc_vcpu_run_hv(struct kvm_vcpu *vcpu)
}
} while (is_kvmppc_resume_guest(r));
- /* Restore userspace EBB and other register values */
- if (cpu_has_feature(CPU_FTR_ARCH_207S)) {
- mtspr(SPRN_EBBHR, ebb_regs[0]);
- mtspr(SPRN_EBBRR, ebb_regs[1]);
- mtspr(SPRN_BESCR, ebb_regs[2]);
- mtspr(SPRN_TAR, user_tar);
- }
- mtspr(SPRN_VRSAVE, user_vrsave);
-
vcpu->arch.state = KVMPPC_VCPU_NOTREADY;
atomic_dec(&kvm->arch.vcpus_running);
