mirror of https://gitee.com/openkylin/linux.git
arm64: KVM: Simplify HYP init/teardown
Now that we only have the "merged page tables" case to deal with, there is a bunch of things we can simplify in the HYP code (both at init and teardown time). Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
This commit is contained in:
Marc Zyngier
Christoffer Dall
parent
0535a3e2b2
commit
3421e9d88d
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@ -48,7 +48,6 @@
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int __attribute_const__ kvm_target_cpu(void);
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int kvm_reset_vcpu(struct kvm_vcpu *vcpu);
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int kvm_arch_dev_ioctl_check_extension(long ext);
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unsigned long kvm_hyp_reset_entry(void);
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void __extended_idmap_trampoline(phys_addr_t boot_pgd, phys_addr_t idmap_start);
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struct kvm_arch {
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@ -357,19 +356,14 @@ static inline void __cpu_init_hyp_mode(phys_addr_t boot_pgd_ptr,
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* Call initialization code, and switch to the full blown
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* HYP code.
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*/
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__kvm_call_hyp((void *)boot_pgd_ptr, pgd_ptr,
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hyp_stack_ptr, vector_ptr);
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__kvm_call_hyp((void *)pgd_ptr, hyp_stack_ptr, vector_ptr);
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}
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void __kvm_hyp_teardown(void);
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static inline void __cpu_reset_hyp_mode(phys_addr_t boot_pgd_ptr,
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phys_addr_t phys_idmap_start)
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{
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/*
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* Call reset code, and switch back to stub hyp vectors.
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* Uses __kvm_call_hyp() to avoid kaslr's kvm_ksym_ref() translation.
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*/
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__kvm_call_hyp((void *)kvm_hyp_reset_entry(),
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boot_pgd_ptr, phys_idmap_start);
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kvm_call_hyp(__kvm_hyp_teardown, phys_idmap_start);
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}
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static inline void kvm_arch_hardware_unsetup(void) {}
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@ -53,10 +53,9 @@ __invalid:
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b .
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/*
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* x0: HYP boot pgd
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* x1: HYP pgd
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* x2: HYP stack
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* x3: HYP vectors
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* x0: HYP pgd
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* x1: HYP stack
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* x2: HYP vectors
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*/
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__do_hyp_init:
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@ -110,71 +109,27 @@ __do_hyp_init:
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msr sctlr_el2, x4
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isb
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/* Skip the trampoline dance if we merged the boot and runtime PGDs */
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cmp x0, x1
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b.eq merged
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/* MMU is now enabled. Get ready for the trampoline dance */
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ldr x4, =TRAMPOLINE_VA
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adr x5, target
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bfi x4, x5, #0, #PAGE_SHIFT
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br x4
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target: /* We're now in the trampoline code, switch page tables */
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msr ttbr0_el2, x1
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isb
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/* Invalidate the old TLBs */
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tlbi alle2
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dsb sy
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merged:
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/* Set the stack and new vectors */
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kern_hyp_va x1
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mov sp, x1
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kern_hyp_va x2
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mov sp, x2
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kern_hyp_va x3
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msr vbar_el2, x3
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msr vbar_el2, x2
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/* Hello, World! */
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eret
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ENDPROC(__kvm_hyp_init)
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/*
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* Reset kvm back to the hyp stub. This is the trampoline dance in
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* reverse. If kvm used an extended idmap, __extended_idmap_trampoline
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* calls this code directly in the idmap. In this case switching to the
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* boot tables is a no-op.
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*
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* x0: HYP boot pgd
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* x1: HYP phys_idmap_start
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* Reset kvm back to the hyp stub.
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*/
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ENTRY(__kvm_hyp_reset)
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/* We're in trampoline code in VA, switch back to boot page tables */
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msr ttbr0_el2, x0
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isb
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/* Ensure the PA branch doesn't find a stale tlb entry or stale code. */
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ic iallu
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tlbi alle2
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dsb sy
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isb
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/* Branch into PA space */
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adr x0, 1f
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bfi x1, x0, #0, #PAGE_SHIFT
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br x1
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/* We're now in idmap, disable MMU */
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1: mrs x0, sctlr_el2
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mrs x0, sctlr_el2
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ldr x1, =SCTLR_ELx_FLAGS
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bic x0, x0, x1 // Clear SCTL_M and etc
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msr sctlr_el2, x0
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isb
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/* Invalidate the old TLBs */
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tlbi alle2
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dsb sy
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/* Install stub vectors */
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adr_l x0, __hyp_stub_vectors
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msr vbar_el2, x0
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@ -164,22 +164,3 @@ alternative_endif
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eret
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ENDPROC(__fpsimd_guest_restore)
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/*
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* When using the extended idmap, we don't have a trampoline page we can use
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* while we switch pages tables during __kvm_hyp_reset. Accessing the idmap
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* directly would be ideal, but if we're using the extended idmap then the
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* idmap is located above HYP_PAGE_OFFSET, and the address will be masked by
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* kvm_call_hyp using kern_hyp_va.
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*
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* x0: HYP boot pgd
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* x1: HYP phys_idmap_start
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*/
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ENTRY(__extended_idmap_trampoline)
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mov x4, x1
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adr_l x3, __kvm_hyp_reset
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/* insert __kvm_hyp_reset()s offset into phys_idmap_start */
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bfi x4, x3, #0, #PAGE_SHIFT
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br x4
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ENDPROC(__extended_idmap_trampoline)
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@ -62,6 +62,21 @@ ENTRY(__vhe_hyp_call)
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isb
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ret
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ENDPROC(__vhe_hyp_call)
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/*
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* Compute the idmap address of __kvm_hyp_reset based on the idmap
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* start passed as a parameter, and jump there.
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*
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* x0: HYP phys_idmap_start
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*/
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ENTRY(__kvm_hyp_teardown)
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mov x4, x0
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adr_l x3, __kvm_hyp_reset
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/* insert __kvm_hyp_reset()s offset into phys_idmap_start */
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bfi x4, x3, #0, #PAGE_SHIFT
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br x4
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ENDPROC(__kvm_hyp_teardown)
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el1_sync: // Guest trapped into EL2
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save_x0_to_x3
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@ -132,14 +132,3 @@ int kvm_reset_vcpu(struct kvm_vcpu *vcpu)
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/* Reset timer */
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return kvm_timer_vcpu_reset(vcpu, cpu_vtimer_irq);
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}
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unsigned long kvm_hyp_reset_entry(void)
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{
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/*
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* KVM is running with merged page tables, which don't have the
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* trampoline page mapped. We know the idmap is still mapped,
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* but can't be called into directly. Use
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* __extended_idmap_trampoline to do the call.
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*/
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return (unsigned long)kvm_ksym_ref(__extended_idmap_trampoline);
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}
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