Detect supported guest-memfd flags by the current kernel, and reject creations of guest-memfd using invalid flags. When the cap isn't available, then no flag is supported.
Signed-off-by: Peter Xu <[email protected]> --- accel/kvm/kvm-all.c | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c index 96c194ce54..f477014126 100644 --- a/accel/kvm/kvm-all.c +++ b/accel/kvm/kvm-all.c @@ -108,6 +108,7 @@ static int kvm_sstep_flags; static bool kvm_immediate_exit; static uint64_t kvm_supported_memory_attributes; static bool kvm_guest_memfd_supported; +static uint64_t kvm_guest_memfd_flags_supported; static hwaddr kvm_max_slot_size = ~0; static const KVMCapabilityInfo kvm_required_capabilites[] = { @@ -2787,6 +2788,10 @@ static int kvm_init(AccelState *as, MachineState *ms) kvm_guest_memfd_supported = kvm_vm_check_extension(s, KVM_CAP_GUEST_MEMFD) && kvm_vm_check_extension(s, KVM_CAP_USER_MEMORY2); + + ret = kvm_vm_check_extension(s, KVM_CAP_GUEST_MEMFD_FLAGS); + kvm_guest_memfd_flags_supported = ret > 0 ? ret : 0; + kvm_pre_fault_memory_supported = kvm_vm_check_extension(s, KVM_CAP_PRE_FAULT_MEMORY); if (s->kernel_irqchip_split == ON_OFF_AUTO_AUTO) { @@ -4492,6 +4497,12 @@ int kvm_create_guest_memfd(uint64_t size, uint64_t flags, Error **errp) return -1; } + if (flags & ~kvm_guest_memfd_flags_supported) { + error_setg(errp, "KVM does not support guest-memfd flag: 0x%"PRIx64, + flags & ~kvm_guest_memfd_flags_supported); + return -1; + } + fd = kvm_vm_ioctl(kvm_state, KVM_CREATE_GUEST_MEMFD, &guest_memfd); if (fd < 0) { error_setg_errno(errp, errno, "Error creating KVM guest_memfd"); -- 2.50.1
