Re: [PATCH v5 5/7] KVM: selftests: Make arm64's MMIO ucall multi-VM friendly
From: Andrew Jones <hidden>
Date: 2022-08-29 16:19:54
Also in:
kvm, kvm-riscv, kvmarm, linux-riscv, lkml, llvm
On Thu, Aug 25, 2022 at 11:25:20PM +0000, Sean Christopherson wrote:
Fix a mostly-theoretical bug where ARM's ucall MMIO setup could result in different VMs stomping on each other by cloberring the global pointer. Fix the most obvious issue by saving the MMIO gpa into the VM. A more subtle bug is that creating VMs in parallel (on multiple tasks) could result in a VM using the wrong address. Synchronizing a global to a guest effectively snapshots the value on a per-VM basis, i.e. the "global" is already prepped to work with multiple VMs, but setting the global in the host is not thread-safe. To fix that bug, add write_guest_global() to allow stuffing a VM's copy of a "global" without modifying the host value. Signed-off-by: Sean Christopherson <seanjc@google.com> --- .../selftests/kvm/include/kvm_util_base.h | 15 +++++++++++++++ .../testing/selftests/kvm/lib/aarch64/ucall.c | 19 ++++++++++++++----- 2 files changed, 29 insertions(+), 5 deletions(-)
Reviewed-by: Andrew Jones <redacted> _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel