diff options
| -rw-r--r-- | arch/arm64/include/asm/kvm_host.h | 3 | ||||
| -rw-r--r-- | arch/arm64/kvm/hyp-init.S | 5 | ||||
| -rw-r--r-- | arch/arm64/kvm/hyp/entry.S | 19 | ||||
| -rw-r--r-- | arch/arm64/kvm/reset.c | 30 |
4 files changed, 49 insertions, 8 deletions
diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h index 295fdaafabd5..580a5232d217 100644 --- a/arch/arm64/include/asm/kvm_host.h +++ b/arch/arm64/include/asm/kvm_host.h @@ -48,7 +48,8 @@ int __attribute_const__ kvm_target_cpu(void); int kvm_reset_vcpu(struct kvm_vcpu *vcpu); int kvm_arch_dev_ioctl_check_extension(long ext); -phys_addr_t kvm_hyp_reset_entry(void); +unsigned long kvm_hyp_reset_entry(void); +void __extended_idmap_trampoline(phys_addr_t boot_pgd, phys_addr_t idmap_start); struct kvm_arch { /* The VMID generation used for the virt. memory system */ diff --git a/arch/arm64/kvm/hyp-init.S b/arch/arm64/kvm/hyp-init.S index 0f474d278987..3270d392970d 100644 --- a/arch/arm64/kvm/hyp-init.S +++ b/arch/arm64/kvm/hyp-init.S @@ -142,6 +142,11 @@ merged: ENDPROC(__kvm_hyp_init) /* + * Reset kvm back to the hyp stub. This is the trampoline dance in + * reverse. If kvm used an extended idmap, __extended_idmap_trampoline + * calls this code directly in the idmap. In this case switching to the + * boot tables is a no-op. + * * x0: HYP boot pgd * x1: HYP phys_idmap_start */ diff --git a/arch/arm64/kvm/hyp/entry.S b/arch/arm64/kvm/hyp/entry.S index 1050b2b09904..ac65c52d6275 100644 --- a/arch/arm64/kvm/hyp/entry.S +++ b/arch/arm64/kvm/hyp/entry.S @@ -159,3 +159,22 @@ ENTRY(__fpsimd_guest_restore) eret ENDPROC(__fpsimd_guest_restore) + +/* + * When using the extended idmap, we don't have a trampoline page we can use + * while we switch pages tables during __kvm_hyp_reset. Accessing the idmap + * directly would be ideal, but if we're using the extended idmap then the + * idmap is located above HYP_PAGE_OFFSET, and the address will be masked by + * kvm_call_hyp using kern_hyp_va. + * + * x0: HYP boot pgd + * x1: HYP phys_idmap_start + */ +ENTRY(__extended_idmap_trampoline) + mov x4, x1 + adr_l x3, __kvm_hyp_reset + + /* insert __kvm_hyp_reset()s offset into phys_idmap_start */ + bfi x4, x3, #0, #PAGE_SHIFT + br x4 +ENDPROC(__extended_idmap_trampoline) diff --git a/arch/arm64/kvm/reset.c b/arch/arm64/kvm/reset.c index 03e909069691..e515b85220b4 100644 --- a/arch/arm64/kvm/reset.c +++ b/arch/arm64/kvm/reset.c @@ -114,12 +114,28 @@ int kvm_reset_vcpu(struct kvm_vcpu *vcpu) extern char __hyp_idmap_text_start[]; -phys_addr_t kvm_hyp_reset_entry(void) +unsigned long kvm_hyp_reset_entry(void) { - unsigned long offset; - - offset = (unsigned long)__kvm_hyp_reset - - ((unsigned long)__hyp_idmap_text_start & PAGE_MASK); - - return TRAMPOLINE_VA + offset; + if (!__kvm_cpu_uses_extended_idmap()) { + unsigned long offset; + + /* + * Find the address of __kvm_hyp_reset() in the trampoline page. + * This is present in the running page tables, and the boot page + * tables, so we call the code here to start the trampoline + * dance in reverse. + */ + offset = (unsigned long)__kvm_hyp_reset + - ((unsigned long)__hyp_idmap_text_start & PAGE_MASK); + + return TRAMPOLINE_VA + offset; + } else { + /* + * KVM is running with merged page tables, which don't have the + * trampoline page mapped. We know the idmap is still mapped, + * but can't be called into directly. Use + * __extended_idmap_trampoline to do the call. + */ + return (unsigned long)kvm_ksym_ref(__extended_idmap_trampoline); + } } |