From: Paul Mackerras Date: Mon, 11 Sep 2017 06:05:30 +0000 (+1000) Subject: KVM: PPC: Book3S HV: Hold kvm->lock around call to kvmppc_update_lpcr X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=cf5f6f3125241853462334b1bc696f3c3c492178;p=GitHub%2Fmoto-9609%2Fandroid_kernel_motorola_exynos9610.git KVM: PPC: Book3S HV: Hold kvm->lock around call to kvmppc_update_lpcr Commit 468808bd35c4 ("KVM: PPC: Book3S HV: Set process table for HPT guests on POWER9", 2017-01-30) added a call to kvmppc_update_lpcr() which doesn't hold the kvm->lock mutex around the call, as required. This adds the lock/unlock pair, and for good measure, includes the kvmppc_setup_partition_table() call in the locked region, since it is altering global state of the VM. This error appears not to have any fatal consequences for the host; the consequences would be that the VCPUs could end up running with different LPCR values, or an update to the LPCR value by userspace using the one_reg interface could get overwritten, or the update done by kvmhv_configure_mmu() could get overwritten. Cc: stable@vger.kernel.org # v4.10+ Fixes: 468808bd35c4 ("KVM: PPC: Book3S HV: Set process table for HPT guests on POWER9") Signed-off-by: Paul Mackerras --- diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c index 18e974a34fce..a7177c284f9b 100644 --- a/arch/powerpc/kvm/book3s_hv.c +++ b/arch/powerpc/kvm/book3s_hv.c @@ -4212,11 +4212,13 @@ static int kvmhv_configure_mmu(struct kvm *kvm, struct kvm_ppc_mmuv3_cfg *cfg) if ((cfg->process_table & PRTS_MASK) > 24) return -EINVAL; + mutex_lock(&kvm->lock); kvm->arch.process_table = cfg->process_table; kvmppc_setup_partition_table(kvm); lpcr = (cfg->flags & KVM_PPC_MMUV3_GTSE) ? LPCR_GTSE : 0; kvmppc_update_lpcr(kvm, lpcr, LPCR_GTSE); + mutex_unlock(&kvm->lock); return 0; }