From 9b19221dbbc86a75294da3a3e4356be7288c4110 Mon Sep 17 00:00:00 2001 From: Quentin Perret Date: Wed, 15 Dec 2021 16:12:23 +0000 Subject: [PATCH] BACKPORT: KVM: arm64: Introduce kvm_share_hyp() The create_hyp_mappings() function can currently be called at any point in time. However, its behaviour in protected mode changes widely depending on when it is being called. Prior to KVM init, it is used to create the temporary page-table used to bring-up the hypervisor, and later on it is transparently turned into a 'share' hypercall when the kernel has lost control over the hypervisor stage-1. In order to prepare the ground for also unsharing pages with the hypervisor during guest teardown, introduce a kvm_share_hyp() function to make it clear in which places a share hypercall should be expected, as we will soon need a matching unshare hypercall in all those places. Signed-off-by: Quentin Perret Signed-off-by: Marc Zyngier Link: https://lore.kernel.org/r/20211215161232.1480836-7-qperret@google.com (cherry picked from commit 3f868e142c0bb052a1c15fd3ceca1391604e2e69) [willdeacon@: Fix conflict in kvm_arch_vcpu_run_map_fp() in same way as upstream merge commit 2d761dbf7ff4 ("Merge branch kvm-arm64/fpsimd-tracking into kvmarm-master/next")] Signed-off-by: Will Deacon Bug: 233587962 Bug: 233588291 Change-Id: Id3ba033a51550e5aada862d6af06773d0be833fb --- arch/arm64/include/asm/kvm_mmu.h | 1 + arch/arm64/kvm/arm.c | 4 ++-- arch/arm64/kvm/fpsimd.c | 8 +++----- arch/arm64/kvm/mmu.c | 27 +++++++++++++++++++++------ arch/arm64/kvm/reset.c | 2 +- 5 files changed, 28 insertions(+), 14 deletions(-) diff --git a/arch/arm64/include/asm/kvm_mmu.h b/arch/arm64/include/asm/kvm_mmu.h index 02d378887743..185d0f62b724 100644 --- a/arch/arm64/include/asm/kvm_mmu.h +++ b/arch/arm64/include/asm/kvm_mmu.h @@ -150,6 +150,7 @@ static __always_inline unsigned long __kern_hyp_va(unsigned long v) #include #include +int kvm_share_hyp(void *from, void *to); int create_hyp_mappings(void *from, void *to, enum kvm_pgtable_prot prot); int create_hyp_io_mappings(phys_addr_t phys_addr, size_t size, void __iomem **kaddr, diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c index 488e98258cb6..306b9fe3b133 100644 --- a/arch/arm64/kvm/arm.c +++ b/arch/arm64/kvm/arm.c @@ -146,7 +146,7 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type) if (ret) return ret; - ret = create_hyp_mappings(kvm, kvm + 1, PAGE_HYP); + ret = kvm_share_hyp(kvm, kvm + 1); if (ret) goto out_free_stage2_pgd; @@ -350,7 +350,7 @@ int kvm_arch_vcpu_create(struct kvm_vcpu *vcpu) if (err) return err; - return create_hyp_mappings(vcpu, vcpu + 1, PAGE_HYP); + return kvm_share_hyp(vcpu, vcpu + 1); } void kvm_arch_vcpu_postcreate(struct kvm_vcpu *vcpu) diff --git a/arch/arm64/kvm/fpsimd.c b/arch/arm64/kvm/fpsimd.c index ee3291de04be..86899d3aa9a9 100644 --- a/arch/arm64/kvm/fpsimd.c +++ b/arch/arm64/kvm/fpsimd.c @@ -30,12 +30,10 @@ int kvm_arch_vcpu_run_map_fp(struct kvm_vcpu *vcpu) struct user_fpsimd_state *fpsimd = ¤t->thread.uw.fpsimd_state; /* Make sure the host task fpsimd state is visible to hyp: */ - ret = create_hyp_mappings(fpsimd, fpsimd + 1, PAGE_HYP); - if (ret) - goto error; + ret = kvm_share_hyp(fpsimd, fpsimd + 1); + if (!ret) + vcpu->arch.host_fpsimd_state = kern_hyp_va(fpsimd); - vcpu->arch.host_fpsimd_state = kern_hyp_va(fpsimd); -error: return ret; } diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c index ea840fa223b5..872137fb5e0f 100644 --- a/arch/arm64/kvm/mmu.c +++ b/arch/arm64/kvm/mmu.c @@ -299,6 +299,25 @@ static int pkvm_share_hyp(phys_addr_t start, phys_addr_t end) return 0; } +int kvm_share_hyp(void *from, void *to) +{ + if (is_kernel_in_hyp_mode()) + return 0; + + /* + * The share hcall maps things in the 'fixed-offset' region of the hyp + * VA space, so we can only share physically contiguous data-structures + * for now. + */ + if (is_vmalloc_or_module_addr(from) || is_vmalloc_or_module_addr(to)) + return -EINVAL; + + if (kvm_host_owns_hyp_mappings()) + return create_hyp_mappings(from, to, PAGE_HYP); + + return pkvm_share_hyp(__pa(from), __pa(to)); +} + /** * create_hyp_mappings - duplicate a kernel virtual address range in Hyp mode * @from: The virtual kernel start address of the range @@ -319,12 +338,8 @@ int create_hyp_mappings(void *from, void *to, enum kvm_pgtable_prot prot) if (is_kernel_in_hyp_mode()) return 0; - if (!kvm_host_owns_hyp_mappings()) { - if (WARN_ON(prot != PAGE_HYP)) - return -EPERM; - return pkvm_share_hyp(kvm_kaddr_to_phys(from), - kvm_kaddr_to_phys(to)); - } + if (!kvm_host_owns_hyp_mappings()) + return -EPERM; start = start & PAGE_MASK; end = PAGE_ALIGN(end); diff --git a/arch/arm64/kvm/reset.c b/arch/arm64/kvm/reset.c index c2a5a3c5cec7..ae9c92fee7ed 100644 --- a/arch/arm64/kvm/reset.c +++ b/arch/arm64/kvm/reset.c @@ -113,7 +113,7 @@ static int kvm_vcpu_finalize_sve(struct kvm_vcpu *vcpu) if (!buf) return -ENOMEM; - ret = create_hyp_mappings(buf, buf + reg_sz, PAGE_HYP); + ret = kvm_share_hyp(buf, buf + reg_sz); if (ret) { kfree(buf); return ret;