Hi Andre, On 06/10/2017 16:38, Andre Przywara wrote: > 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 OK. I will add this check. Thanks Eric > > 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 >>
