Hi, On 27/09/17 14:28, Eric Auger wrote: > At the moment vgic_its_process_commands() does not > check the CBASER is valid before processing any command. > Let's fix that. Good catch, but actually it goes a bit further: "When GITS_CTLR.Enabled is written from 0 to 1 behavior is UNPREDICTABLE if any of the following conditions are true: · GITS_CBASER.Valid == 0. ... " So I think we need to check it upon setting CTLR.Enabled. I did this in Xen, but forgot to fix this in KVM as well: https://xenbits.xen.org/gitweb/?p=xen.git;a=blob;f=xen/arch/arm/vgic-v3-its.c;hb=HEAD#l1164 Cheers, Andre. > > Also rename cbaser local variable into cbaser_pa to avoid > any confusion with the full register. > > Signed-off-by: Eric Auger <eric.auger@xxxxxxxxxx> > --- > virt/kvm/arm/vgic/vgic-its.c | 13 ++++++++----- > 1 file changed, 8 insertions(+), 5 deletions(-) > > diff --git a/virt/kvm/arm/vgic/vgic-its.c b/virt/kvm/arm/vgic/vgic-its.c > index 60ecf91..720552c 100644 > --- a/virt/kvm/arm/vgic/vgic-its.c > +++ b/virt/kvm/arm/vgic/vgic-its.c > @@ -1301,17 +1301,20 @@ static void vgic_mmio_write_its_cbaser(struct kvm *kvm, struct vgic_its *its, > /* Must be called with the cmd_lock held. */ > static void vgic_its_process_commands(struct kvm *kvm, struct vgic_its *its) > { > - gpa_t cbaser; > + gpa_t cbaser_pa; > u64 cmd_buf[4]; > > - /* Commands are only processed when the ITS is enabled. */ > - if (!its->enabled) > + /* > + * Commands are only processed when the ITS is enabled and > + * CBASER is valid > + */ > + if (!its->enabled || (!(its->cbaser & GITS_CBASER_VALID))) > return; > > - cbaser = CBASER_ADDRESS(its->cbaser); > + cbaser_pa = CBASER_ADDRESS(its->cbaser); > > while (its->cwriter != its->creadr) { > - int ret = kvm_read_guest(kvm, cbaser + its->creadr, > + int ret = kvm_read_guest(kvm, cbaser_pa + its->creadr, > cmd_buf, ITS_CMD_SIZE); > /* > * If kvm_read_guest() fails, this could be due to the guest >
