Re: [Xen-devel] [XTF PATCH 14/16] vvmx: test vmxon in VMX root w/ CPL = 3 and w/o current VMCS

[Haozhong Zhang <haozhong.zhang@xxxxxxxxx>]

On 12/16/16 20:59 +0000, Andrew Cooper wrote:
> On 16/12/16 13:43, Haozhong Zhang wrote:
> > Fault #GP(0) is expected in this test.
> >
> > Signed-off-by: Haozhong Zhang <haozhong.zhang@xxxxxxxxx>
> > ---
> >  tests/vvmx/vmxon.c | 29 +++++++++++++++++++++++++++++
> >  1 file changed, 29 insertions(+)
> >
> > diff --git a/tests/vvmx/vmxon.c b/tests/vvmx/vmxon.c
> > index 0664a48..ec7ee7e 100644
> > --- a/tests/vvmx/vmxon.c
> > +++ b/tests/vvmx/vmxon.c
> > @@ -3,6 +3,7 @@
> >  #include "util.h"
> >
> >  static uint8_t vmxon_region[PAGE_SIZE] __aligned(PAGE_SIZE);
> > +static uint8_t vmxon_region_2nd[PAGE_SIZE] __aligned(PAGE_SIZE);
> You introduce vmxon_region_2nd here, but reference it in the previous patch.
I must have made mistakes when separating patch 13 - 16.

> However, I am not sure of its purpose.  Why cant you reuse the previous
> host state area?
Intel SDM says SW should not access or modify the VXMON rgion of a
logical processor between vmxon and vmxoff. Though I have tested on
real hardware whether reusing VMXON region would cause any trouble, I
still want to exclude that possibility/noise from this test.

> >  /**
> >   * vmxon with CR4.VMXE cleared
> > @@ -165,6 +166,31 @@ static bool test_vmxon_in_root_cpl0_novmcs(void)
> >                                VMXERR_VMFAIL_INVALID, 0, 0);
> >  }
> >
> > +static unsigned long vmxon_in_root_user(void)
> > +{
> > +    exinfo_t fault;
> > +    unsigned long ret = vmxon((uint64_t)vmxon_region_2nd, &fault);
> > +
> > +    return (ret << 32) | fault;
> > +}
> I have a pending patch for exec_user_param() (originally written for a
> test which I subsequently reimplemented differently).
>
> I have just pushed it for you to use.  You can have one common
> user_vmxon() and pass a variable host region to it, rather than having
> an almost-entirely duplicate function.
Thank you! I can use the dedicated bits in exinfo_t as you suggested
in previous patch.

Haozhong

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