[PATCH v4 40/43] arm64: RME: Provide register list for unfinalized RME RECs
From: Steven Price <steven.price@arm.com>
Date: 2024-08-21 15:41:33
Also in:
kvm, kvmarm, linux-arm-kernel, lkml
Subsystem:
arm64 port (aarch64 architecture), kernel virtual machine for arm64 (kvm/arm64), the rest · Maintainers:
Catalin Marinas, Will Deacon, Marc Zyngier, Oliver Upton, Linus Torvalds
From: Jean-Philippe Brucker <redacted> KVM_GET_REG_LIST should not be called before SVE is finalized. The ioctl handler currently returns -EPERM in this case. But because it uses kvm_arm_vcpu_is_finalized(), it now also rejects the call for unfinalized REC even though finalizing the REC can only be done late, after Realm descriptor creation. Move the check to copy_sve_reg_indices(). One adverse side effect of this change is that a KVM_GET_REG_LIST call that only probes for the array size will now succeed even if SVE is not finalized, but that seems harmless since the following KVM_GET_REG_LIST with the full array will fail. Signed-off-by: Jean-Philippe Brucker <redacted> Signed-off-by: Steven Price <steven.price@arm.com> --- arch/arm64/kvm/arm.c | 4 ---- arch/arm64/kvm/guest.c | 9 +++------ 2 files changed, 3 insertions(+), 10 deletions(-)
diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index bd79a928d036..05d9062470c2 100644
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c@@ -1843,10 +1843,6 @@ long kvm_arch_vcpu_ioctl(struct file *filp, if (unlikely(!kvm_vcpu_initialized(vcpu))) break; - r = -EPERM; - if (!kvm_arm_vcpu_is_finalized(vcpu)) - break; - r = -EFAULT; if (copy_from_user(®_list, user_list, sizeof(reg_list))) break;
diff --git a/arch/arm64/kvm/guest.c b/arch/arm64/kvm/guest.c
index e00b72fba33d..b12b5e4ddd8c 100644
--- a/arch/arm64/kvm/guest.c
+++ b/arch/arm64/kvm/guest.c@@ -653,12 +653,9 @@ static unsigned long num_sve_regs(const struct kvm_vcpu *vcpu) { const unsigned int slices = vcpu_sve_slices(vcpu); - if (!vcpu_has_sve(vcpu)) + if (!vcpu_has_sve(vcpu) || !kvm_arm_vcpu_sve_finalized(vcpu)) return 0; - /* Policed by KVM_GET_REG_LIST: */ - WARN_ON(!kvm_arm_vcpu_sve_finalized(vcpu)); - return slices * (SVE_NUM_PREGS + SVE_NUM_ZREGS + 1 /* FFR */) + 1; /* KVM_REG_ARM64_SVE_VLS */ }
@@ -674,8 +671,8 @@ static int copy_sve_reg_indices(const struct kvm_vcpu *vcpu, if (!vcpu_has_sve(vcpu)) return 0; - /* Policed by KVM_GET_REG_LIST: */ - WARN_ON(!kvm_arm_vcpu_sve_finalized(vcpu)); + if (!kvm_arm_vcpu_sve_finalized(vcpu)) + return -EPERM; /* * Enumerate this first, so that userspace can save/restore in
--
2.34.1