From 3c1e716508335eb132c9349cb1a1716c8f7e3d2e Mon Sep 17 00:00:00 2001 From: Marc Zyngier Date: Fri, 19 Dec 2014 16:05:31 +0000 Subject: arm/arm64: KVM: Use set/way op trapping to track the state of the caches Trying to emulate the behaviour of set/way cache ops is fairly pointless, as there are too many ways we can end-up missing stuff. Also, there is some system caches out there that simply ignore set/way operations. So instead of trying to implement them, let's convert it to VA ops, and use them as a way to re-enable the trapping of VM ops. That way, we can detect the point when the MMU/caches are turned off, and do a full VM flush (which is what the guest was trying to do anyway). This allows a 32bit zImage to boot on the APM thingy, and will probably help bootloaders in general. Signed-off-by: Marc Zyngier Signed-off-by: Christoffer Dall --- arch/arm64/include/asm/kvm_emulate.h | 10 +++++ arch/arm64/include/asm/kvm_host.h | 3 -- arch/arm64/include/asm/kvm_mmu.h | 3 +- arch/arm64/kvm/sys_regs.c | 75 +++++------------------------------- 4 files changed, 22 insertions(+), 69 deletions(-) (limited to 'arch/arm64') diff --git a/arch/arm64/include/asm/kvm_emulate.h b/arch/arm64/include/asm/kvm_emulate.h index 865a7e28ea2d..3cb4c856b10d 100644 --- a/arch/arm64/include/asm/kvm_emulate.h +++ b/arch/arm64/include/asm/kvm_emulate.h @@ -45,6 +45,16 @@ static inline void vcpu_reset_hcr(struct kvm_vcpu *vcpu) vcpu->arch.hcr_el2 &= ~HCR_RW; } +static inline unsigned long vcpu_get_hcr(struct kvm_vcpu *vcpu) +{ + return vcpu->arch.hcr_el2; +} + +static inline void vcpu_set_hcr(struct kvm_vcpu *vcpu, unsigned long hcr) +{ + vcpu->arch.hcr_el2 = hcr; +} + static inline unsigned long *vcpu_pc(const struct kvm_vcpu *vcpu) { return (unsigned long *)&vcpu_gp_regs(vcpu)->regs.pc; diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h index 0b7dfdb931df..acd101a9014d 100644 --- a/arch/arm64/include/asm/kvm_host.h +++ b/arch/arm64/include/asm/kvm_host.h @@ -116,9 +116,6 @@ struct kvm_vcpu_arch { * Anything that is not used directly from assembly code goes * here. */ - /* dcache set/way operation pending */ - int last_pcpu; - cpumask_t require_dcache_flush; /* Don't run the guest */ bool pause; diff --git a/arch/arm64/include/asm/kvm_mmu.h b/arch/arm64/include/asm/kvm_mmu.h index 14a74f136272..92d22e94a79b 100644 --- a/arch/arm64/include/asm/kvm_mmu.h +++ b/arch/arm64/include/asm/kvm_mmu.h @@ -260,7 +260,8 @@ static inline void coherent_cache_guest_page(struct kvm_vcpu *vcpu, hva_t hva, #define kvm_virt_to_phys(x) __virt_to_phys((unsigned long)(x)) -void stage2_flush_vm(struct kvm *kvm); +void kvm_set_way_flush(struct kvm_vcpu *vcpu); +void kvm_toggle_cache(struct kvm_vcpu *vcpu, bool was_enabled); #endif /* __ASSEMBLY__ */ #endif /* __ARM64_KVM_MMU_H__ */ diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c index 3d7c2df89946..f31e8bb2bc5b 100644 --- a/arch/arm64/kvm/sys_regs.c +++ b/arch/arm64/kvm/sys_regs.c @@ -69,68 +69,31 @@ static u32 get_ccsidr(u32 csselr) return ccsidr; } -static void do_dc_cisw(u32 val) -{ - asm volatile("dc cisw, %x0" : : "r" (val)); - dsb(ish); -} - -static void do_dc_csw(u32 val) -{ - asm volatile("dc csw, %x0" : : "r" (val)); - dsb(ish); -} - -/* See note at ARM ARM B1.14.4 */ +/* + * See note at ARMv7 ARM B1.14.4 (TL;DR: S/W ops are not easily virtualized). + */ static bool access_dcsw(struct kvm_vcpu *vcpu, const struct sys_reg_params *p, const struct sys_reg_desc *r) { - unsigned long val; - int cpu; - if (!p->is_write) return read_from_write_only(vcpu, p); - cpu = get_cpu(); - - cpumask_setall(&vcpu->arch.require_dcache_flush); - cpumask_clear_cpu(cpu, &vcpu->arch.require_dcache_flush); - - /* If we were already preempted, take the long way around */ - if (cpu != vcpu->arch.last_pcpu) { - flush_cache_all(); - goto done; - } - - val = *vcpu_reg(vcpu, p->Rt); - - switch (p->CRm) { - case 6: /* Upgrade DCISW to DCCISW, as per HCR.SWIO */ - case 14: /* DCCISW */ - do_dc_cisw(val); - break; - - case 10: /* DCCSW */ - do_dc_csw(val); - break; - } - -done: - put_cpu(); - + kvm_set_way_flush(vcpu); return true; } /* * Generic accessor for VM registers. Only called as long as HCR_TVM - * is set. + * is set. If the guest enables the MMU, we stop trapping the VM + * sys_regs and leave it in complete control of the caches. */ static bool access_vm_reg(struct kvm_vcpu *vcpu, const struct sys_reg_params *p, const struct sys_reg_desc *r) { unsigned long val; + bool was_enabled = vcpu_has_cache_enabled(vcpu); BUG_ON(!p->is_write); @@ -143,25 +106,7 @@ static bool access_vm_reg(struct kvm_vcpu *vcpu, vcpu_cp15_64_low(vcpu, r->reg) = val & 0xffffffffUL; } - return true; -} - -/* - * SCTLR_EL1 accessor. Only called as long as HCR_TVM is set. If the - * guest enables the MMU, we stop trapping the VM sys_regs and leave - * it in complete control of the caches. - */ -static bool access_sctlr(struct kvm_vcpu *vcpu, - const struct sys_reg_params *p, - const struct sys_reg_desc *r) -{ - access_vm_reg(vcpu, p, r); - - if (vcpu_has_cache_enabled(vcpu)) { /* MMU+Caches enabled? */ - vcpu->arch.hcr_el2 &= ~HCR_TVM; - stage2_flush_vm(vcpu->kvm); - } - + kvm_toggle_cache(vcpu, was_enabled); return true; } @@ -377,7 +322,7 @@ static const struct sys_reg_desc sys_reg_descs[] = { NULL, reset_mpidr, MPIDR_EL1 }, /* SCTLR_EL1 */ { Op0(0b11), Op1(0b000), CRn(0b0001), CRm(0b0000), Op2(0b000), - access_sctlr, reset_val, SCTLR_EL1, 0x00C50078 }, + access_vm_reg, reset_val, SCTLR_EL1, 0x00C50078 }, /* CPACR_EL1 */ { Op0(0b11), Op1(0b000), CRn(0b0001), CRm(0b0000), Op2(0b010), NULL, reset_val, CPACR_EL1, 0 }, @@ -657,7 +602,7 @@ static const struct sys_reg_desc cp14_64_regs[] = { * register). */ static const struct sys_reg_desc cp15_regs[] = { - { Op1( 0), CRn( 1), CRm( 0), Op2( 0), access_sctlr, NULL, c1_SCTLR }, + { Op1( 0), CRn( 1), CRm( 0), Op2( 0), access_vm_reg, NULL, c1_SCTLR }, { Op1( 0), CRn( 2), CRm( 0), Op2( 0), access_vm_reg, NULL, c2_TTBR0 }, { Op1( 0), CRn( 2), CRm( 0), Op2( 1), access_vm_reg, NULL, c2_TTBR1 }, { Op1( 0), CRn( 2), CRm( 0), Op2( 2), access_vm_reg, NULL, c2_TTBCR }, -- cgit v1.2.1