On Fri, Jan 15, 2021 at 03:30:50PM +0100, Hubert Jasudowicz wrote: > This patch is a result of a downstream bug report[1]. Xen fails to > create a HVM domain while running under VMware Fusion 12.1.0 on > a modern Intel Core i9 CPU: > > (XEN) VMX: CPU0 has insufficient CPU-Based Exec Control (b5b9fffe; requires > 2299968c) > (XEN) VMX: failed to initialise. > > It seems that Apple hypervisor API doesn't support this feature[2]. > > Move this bit from minimal required features to optional. > > [1] https://github.com/CERT-Polska/drakvuf-sandbox/issues/418 > [2] https://developer.apple.com/documentation/hypervisor/cpu_based_io_bitmaps > > Signed-off-by: Hubert Jasudowicz <hubert.jasudow...@cert.pl> > --- > xen/arch/x86/hvm/vmx/vmcs.c | 8 +++++--- > xen/include/asm-x86/hvm/vmx/vmcs.h | 2 ++ > 2 files changed, 7 insertions(+), 3 deletions(-) > > diff --git a/xen/arch/x86/hvm/vmx/vmcs.c b/xen/arch/x86/hvm/vmx/vmcs.c > index 164535f8f0..bad4d6e206 100644 > --- a/xen/arch/x86/hvm/vmx/vmcs.c > +++ b/xen/arch/x86/hvm/vmx/vmcs.c > @@ -276,10 +276,10 @@ static int vmx_init_vmcs_config(void) > CPU_BASED_MONITOR_EXITING | > CPU_BASED_MWAIT_EXITING | > CPU_BASED_MOV_DR_EXITING | > - CPU_BASED_ACTIVATE_IO_BITMAP | > CPU_BASED_USE_TSC_OFFSETING | > CPU_BASED_RDTSC_EXITING); > opt = (CPU_BASED_ACTIVATE_MSR_BITMAP | > + CPU_BASED_ACTIVATE_IO_BITMAP | > CPU_BASED_TPR_SHADOW | > CPU_BASED_MONITOR_TRAP_FLAG | > CPU_BASED_ACTIVATE_SECONDARY_CONTROLS); > @@ -1168,8 +1168,10 @@ static int construct_vmcs(struct vcpu *v) > } > > /* I/O access bitmap. */ > - __vmwrite(IO_BITMAP_A, __pa(d->arch.hvm.io_bitmap)); > - __vmwrite(IO_BITMAP_B, __pa(d->arch.hvm.io_bitmap) + PAGE_SIZE); > + if ( cpu_has_vmx_io_bitmap ) { > + __vmwrite(IO_BITMAP_A, __pa(d->arch.hvm.io_bitmap)); > + __vmwrite(IO_BITMAP_B, __pa(d->arch.hvm.io_bitmap) + PAGE_SIZE); > + }
Maybe I'm missing something, but don't you need to expand EXIT_REASON_IO_INSTRUCTION in vmx_vmexit_handler when there's no IO bitmap support so that all the emulation is bypassed and the IO port access is replayed by Xen? I think you don't strictly need to modify EXIT_REASON_IO_INSTRUCTION and can use the existing g2m_ioport_list infrastructure to add the allowed ports present on the bitmap and prevent them from being forwarded to the IOREQ server. Thanks, Roger.
