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authorSean Christopherson <seanjc@google.com>2022-04-15 00:43:43 +0000
committerPaolo Bonzini <pbonzini@redhat.com>2022-04-21 13:16:11 -0400
commit2031f2876896d82aca7e82f84accd9181b9587fb (patch)
tree3738b7477aeb1e7436fa3a01a0a3ff63d0266952 /arch/powerpc
parentfdd6f6ac2e489b9b256cd05a880d13bfdbac7c2e (diff)
KVM: Add helpers to wrap vcpu->srcu_idx and yell if it's abused
Add wrappers to acquire/release KVM's SRCU lock when stashing the index in vcpu->src_idx, along with rudimentary detection of illegal usage, e.g. re-acquiring SRCU and thus overwriting vcpu->src_idx. Because the SRCU index is (currently) either 0 or 1, illegal nesting bugs can go unnoticed for quite some time and only cause problems when the nested lock happens to get a different index. Wrap the WARNs in PROVE_RCU=y, and make them ONCE, otherwise KVM will likely yell so loudly that it will bring the kernel to its knees. Signed-off-by: Sean Christopherson <seanjc@google.com> Tested-by: Fabiano Rosas <farosas@linux.ibm.com> Message-Id: <20220415004343.2203171-4-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/powerpc')
-rw-r--r--arch/powerpc/kvm/book3s_64_mmu_radix.c9
-rw-r--r--arch/powerpc/kvm/book3s_hv_nested.c16
-rw-r--r--arch/powerpc/kvm/book3s_rtas.c4
-rw-r--r--arch/powerpc/kvm/powerpc.c4
4 files changed, 17 insertions, 16 deletions
diff --git a/arch/powerpc/kvm/book3s_64_mmu_radix.c b/arch/powerpc/kvm/book3s_64_mmu_radix.c
index e4ce2a35483f..42851c32ff3b 100644
--- a/arch/powerpc/kvm/book3s_64_mmu_radix.c
+++ b/arch/powerpc/kvm/book3s_64_mmu_radix.c
@@ -168,9 +168,10 @@ int kvmppc_mmu_walk_radix_tree(struct kvm_vcpu *vcpu, gva_t eaddr,
return -EINVAL;
/* Read the entry from guest memory */
addr = base + (index * sizeof(rpte));
- vcpu->srcu_idx = srcu_read_lock(&kvm->srcu);
+
+ kvm_vcpu_srcu_read_lock(vcpu);
ret = kvm_read_guest(kvm, addr, &rpte, sizeof(rpte));
- srcu_read_unlock(&kvm->srcu, vcpu->srcu_idx);
+ kvm_vcpu_srcu_read_unlock(vcpu);
if (ret) {
if (pte_ret_p)
*pte_ret_p = addr;
@@ -246,9 +247,9 @@ int kvmppc_mmu_radix_translate_table(struct kvm_vcpu *vcpu, gva_t eaddr,
/* Read the table to find the root of the radix tree */
ptbl = (table & PRTB_MASK) + (table_index * sizeof(entry));
- vcpu->srcu_idx = srcu_read_lock(&kvm->srcu);
+ kvm_vcpu_srcu_read_lock(vcpu);
ret = kvm_read_guest(kvm, ptbl, &entry, sizeof(entry));
- srcu_read_unlock(&kvm->srcu, vcpu->srcu_idx);
+ kvm_vcpu_srcu_read_unlock(vcpu);
if (ret)
return ret;
diff --git a/arch/powerpc/kvm/book3s_hv_nested.c b/arch/powerpc/kvm/book3s_hv_nested.c
index 9d373f8963ee..c943a051c6e7 100644
--- a/arch/powerpc/kvm/book3s_hv_nested.c
+++ b/arch/powerpc/kvm/book3s_hv_nested.c
@@ -306,10 +306,10 @@ long kvmhv_enter_nested_guest(struct kvm_vcpu *vcpu)
/* copy parameters in */
hv_ptr = kvmppc_get_gpr(vcpu, 4);
regs_ptr = kvmppc_get_gpr(vcpu, 5);
- vcpu->srcu_idx = srcu_read_lock(&vcpu->kvm->srcu);
+ kvm_vcpu_srcu_read_lock(vcpu);
err = kvmhv_read_guest_state_and_regs(vcpu, &l2_hv, &l2_regs,
hv_ptr, regs_ptr);
- srcu_read_unlock(&vcpu->kvm->srcu, vcpu->srcu_idx);
+ kvm_vcpu_srcu_read_unlock(vcpu);
if (err)
return H_PARAMETER;
@@ -410,10 +410,10 @@ long kvmhv_enter_nested_guest(struct kvm_vcpu *vcpu)
byteswap_hv_regs(&l2_hv);
byteswap_pt_regs(&l2_regs);
}
- vcpu->srcu_idx = srcu_read_lock(&vcpu->kvm->srcu);
+ kvm_vcpu_srcu_read_lock(vcpu);
err = kvmhv_write_guest_state_and_regs(vcpu, &l2_hv, &l2_regs,
hv_ptr, regs_ptr);
- srcu_read_unlock(&vcpu->kvm->srcu, vcpu->srcu_idx);
+ kvm_vcpu_srcu_read_unlock(vcpu);
if (err)
return H_AUTHORITY;
@@ -600,16 +600,16 @@ long kvmhv_copy_tofrom_guest_nested(struct kvm_vcpu *vcpu)
goto not_found;
/* Write what was loaded into our buffer back to the L1 guest */
- vcpu->srcu_idx = srcu_read_lock(&vcpu->kvm->srcu);
+ kvm_vcpu_srcu_read_lock(vcpu);
rc = kvm_vcpu_write_guest(vcpu, gp_to, buf, n);
- srcu_read_unlock(&vcpu->kvm->srcu, vcpu->srcu_idx);
+ kvm_vcpu_srcu_read_unlock(vcpu);
if (rc)
goto not_found;
} else {
/* Load the data to be stored from the L1 guest into our buf */
- vcpu->srcu_idx = srcu_read_lock(&vcpu->kvm->srcu);
+ kvm_vcpu_srcu_read_lock(vcpu);
rc = kvm_vcpu_read_guest(vcpu, gp_from, buf, n);
- srcu_read_unlock(&vcpu->kvm->srcu, vcpu->srcu_idx);
+ kvm_vcpu_srcu_read_unlock(vcpu);
if (rc)
goto not_found;
diff --git a/arch/powerpc/kvm/book3s_rtas.c b/arch/powerpc/kvm/book3s_rtas.c
index 0f847f1e5ddd..6808bda0dbc1 100644
--- a/arch/powerpc/kvm/book3s_rtas.c
+++ b/arch/powerpc/kvm/book3s_rtas.c
@@ -229,9 +229,9 @@ int kvmppc_rtas_hcall(struct kvm_vcpu *vcpu)
*/
args_phys = kvmppc_get_gpr(vcpu, 4) & KVM_PAM;
- vcpu->srcu_idx = srcu_read_lock(&vcpu->kvm->srcu);
+ kvm_vcpu_srcu_read_lock(vcpu);
rc = kvm_read_guest(vcpu->kvm, args_phys, &args, sizeof(args));
- srcu_read_unlock(&vcpu->kvm->srcu, vcpu->srcu_idx);
+ kvm_vcpu_srcu_read_unlock(vcpu);
if (rc)
goto fail;
diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c
index 875c30c12db0..533c4232e5ab 100644
--- a/arch/powerpc/kvm/powerpc.c
+++ b/arch/powerpc/kvm/powerpc.c
@@ -425,9 +425,9 @@ int kvmppc_ld(struct kvm_vcpu *vcpu, ulong *eaddr, int size, void *ptr,
return EMULATE_DONE;
}
- vcpu->srcu_idx = srcu_read_lock(&vcpu->kvm->srcu);
+ kvm_vcpu_srcu_read_lock(vcpu);
rc = kvm_read_guest(vcpu->kvm, pte.raddr, ptr, size);
- srcu_read_unlock(&vcpu->kvm->srcu, vcpu->srcu_idx);
+ kvm_vcpu_srcu_read_unlock(vcpu);
if (rc)
return EMULATE_DO_MMIO;