From 70e92c7ee94094d2db8bfe225a8c9b1bde89c26d Mon Sep 17 00:00:00 2001 From: James Hogan Date: Mon, 4 Jul 2016 19:35:11 +0100 Subject: [PATCH] MIPS: KVM: Don't save/restore lo/hi for r6 MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit MIPSr6 doesn't have lo/hi registers, so don't bother saving or restoring them, and don't expose them to userland with the KVM ioctl interface either. In fact the lo/hi registers aren't callee saved in the MIPS ABIs anyway, so there is no need to preserve the host lo/hi values at all when transitioning to and from the guest (which happens via a function call). Signed-off-by: James Hogan Cc: Paolo Bonzini Cc: Radim KrÄmář Cc: Ralf Baechle Cc: linux-mips@linux-mips.org Cc: kvm@vger.kernel.org Signed-off-by: Paolo Bonzini --- arch/mips/kvm/entry.c | 16 ++++------------ arch/mips/kvm/mips.c | 6 ++++++ 2 files changed, 10 insertions(+), 12 deletions(-) diff --git a/arch/mips/kvm/entry.c b/arch/mips/kvm/entry.c index de8b6ec5573f..75ba7c2ecb3d 100644 --- a/arch/mips/kvm/entry.c +++ b/arch/mips/kvm/entry.c @@ -178,12 +178,6 @@ void *kvm_mips_build_vcpu_run(void *addr) UASM_i_SW(&p, i, offsetof(struct pt_regs, regs[i]), K1); } - /* Save hi/lo */ - uasm_i_mflo(&p, V0); - UASM_i_SW(&p, V0, offsetof(struct pt_regs, lo), K1); - uasm_i_mfhi(&p, V1); - UASM_i_SW(&p, V1, offsetof(struct pt_regs, hi), K1); - /* Save host status */ uasm_i_mfc0(&p, V0, C0_STATUS); UASM_i_SW(&p, V0, offsetof(struct pt_regs, cp0_status), K1); @@ -307,12 +301,14 @@ static void *kvm_mips_build_enter_guest(void *addr) UASM_i_LW(&p, i, offsetof(struct kvm_vcpu_arch, gprs[i]), K1); } +#ifndef CONFIG_CPU_MIPSR6 /* Restore hi/lo */ UASM_i_LW(&p, K0, offsetof(struct kvm_vcpu_arch, hi), K1); uasm_i_mthi(&p, K0); UASM_i_LW(&p, K0, offsetof(struct kvm_vcpu_arch, lo), K1); uasm_i_mtlo(&p, K0); +#endif /* Restore the guest's k0/k1 registers */ UASM_i_LW(&p, K0, offsetof(struct kvm_vcpu_arch, gprs[K0]), K1); @@ -408,12 +404,14 @@ void *kvm_mips_build_exit(void *addr) UASM_i_SW(&p, i, offsetof(struct kvm_vcpu_arch, gprs[i]), K1); } +#ifndef CONFIG_CPU_MIPSR6 /* We need to save hi/lo and restore them on the way out */ uasm_i_mfhi(&p, T0); UASM_i_SW(&p, T0, offsetof(struct kvm_vcpu_arch, hi), K1); uasm_i_mflo(&p, T0); UASM_i_SW(&p, T0, offsetof(struct kvm_vcpu_arch, lo), K1); +#endif /* Finally save guest k1 to VCPU */ uasm_i_ehb(&p); @@ -663,12 +661,6 @@ static void *kvm_mips_build_ret_to_host(void *addr) UASM_i_LW(&p, i, offsetof(struct pt_regs, regs[i]), K1); } - UASM_i_LW(&p, K0, offsetof(struct pt_regs, hi), K1); - uasm_i_mthi(&p, K0); - - UASM_i_LW(&p, K0, offsetof(struct pt_regs, lo), K1); - uasm_i_mtlo(&p, K0); - /* Restore RDHWR access */ UASM_i_LA_mostly(&p, K0, (long)&hwrena); uasm_i_lw(&p, K0, uasm_rel_lo((long)&hwrena), K0); diff --git a/arch/mips/kvm/mips.c b/arch/mips/kvm/mips.c index 7c76768ff364..414b00074e29 100644 --- a/arch/mips/kvm/mips.c +++ b/arch/mips/kvm/mips.c @@ -521,8 +521,10 @@ static u64 kvm_mips_get_one_regs[] = { KVM_REG_MIPS_R30, KVM_REG_MIPS_R31, +#ifndef CONFIG_CPU_MIPSR6 KVM_REG_MIPS_HI, KVM_REG_MIPS_LO, +#endif KVM_REG_MIPS_PC, KVM_REG_MIPS_CP0_INDEX, @@ -666,12 +668,14 @@ static int kvm_mips_get_reg(struct kvm_vcpu *vcpu, case KVM_REG_MIPS_R0 ... KVM_REG_MIPS_R31: v = (long)vcpu->arch.gprs[reg->id - KVM_REG_MIPS_R0]; break; +#ifndef CONFIG_CPU_MIPSR6 case KVM_REG_MIPS_HI: v = (long)vcpu->arch.hi; break; case KVM_REG_MIPS_LO: v = (long)vcpu->arch.lo; break; +#endif case KVM_REG_MIPS_PC: v = (long)vcpu->arch.pc; break; @@ -887,12 +891,14 @@ static int kvm_mips_set_reg(struct kvm_vcpu *vcpu, case KVM_REG_MIPS_R1 ... KVM_REG_MIPS_R31: vcpu->arch.gprs[reg->id - KVM_REG_MIPS_R0] = v; break; +#ifndef CONFIG_CPU_MIPSR6 case KVM_REG_MIPS_HI: vcpu->arch.hi = v; break; case KVM_REG_MIPS_LO: vcpu->arch.lo = v; break; +#endif case KVM_REG_MIPS_PC: vcpu->arch.pc = v; break; -- 2.20.1