Re: [PATCH v2 4/4] hvm/svm: Enable CR events

[Alexandru Stefan ISAILA <aisaila@bitdefender.com>]

On Jo, 2018-02-08 at 11:06 -0700, Tamas K Lengyel wrote:
> On Thu, Feb 8, 2018 at 8:25 AM, Alexandru Isaila
> <aisaila@bitdefender.com> wrote:
> >
> > This commit enables controlregister events for svm.
> So this patch enables the event to trigger but where is it being
> handled and forwarded to the monitor ring?
Hi Tamas,

If I've understand your question right, this is handled, like on the
vmx side, on a special case on CR0. If this is not what you are looking
for can you please clarify the question.

Alex
>
> >
> >
> > Signed-off-by: Alexandru Isaila <aisaila@bitdefender.com>
> > ---
> >  xen/arch/x86/hvm/svm/svm.c    | 11 +++++++++++
> >  xen/include/asm-x86/monitor.h |  6 +++---
> >  2 files changed, 14 insertions(+), 3 deletions(-)
> >
> > diff --git a/xen/arch/x86/hvm/svm/svm.c
> > b/xen/arch/x86/hvm/svm/svm.c
> > index 1eadab4..311902f 100644
> > --- a/xen/arch/x86/hvm/svm/svm.c
> > +++ b/xen/arch/x86/hvm/svm/svm.c
> > @@ -60,6 +60,7 @@
> >  #include <asm/apic.h>
> >  #include <asm/debugger.h>
> >  #include <asm/hvm/monitor.h>
> > +#include <asm/monitor.h>
> >  #include <asm/xstate.h>
> >
> >  void svm_asm_do_resume(void);
> > @@ -560,6 +561,16 @@ void svm_update_guest_cr(struct vcpu *v,
> > unsigned int cr)
> >                  svm_fpu_enter(v);
> >          }
> >
> > +        if ( paging_mode_hap(v->domain) )
> > +        {
> > +            uint32_t intercepts = vmcb_get_cr_intercepts(vmcb);
> > +
> > +            /* Trap CR3 updates if CR3 memory events are enabled.
> > */
> > +            if ( v->domain->arch.monitor.write_ctrlreg_enabled &
> > +                 monitor_ctrlreg_bitmask(VM_EVENT_X86_CR3) )
> > +               vmcb_set_cr_intercepts(vmcb, intercepts |
> > CR_INTERCEPT_CR3_WRITE);
> > +        }
> > +
> >          value = v->arch.hvm_vcpu.guest_cr[0] | hw_cr0_mask;
> >          if ( !paging_mode_hap(v->domain) )
> >              value |= X86_CR0_PG | X86_CR0_WP;
> > diff --git a/xen/include/asm-x86/monitor.h b/xen/include/asm-
> > x86/monitor.h
> > index 138c463..b80d217 100644
> > --- a/xen/include/asm-x86/monitor.h
> > +++ b/xen/include/asm-x86/monitor.h
> > @@ -79,8 +79,7 @@ static inline uint32_t
> > arch_monitor_get_capabilities(struct domain *d)
> >
> >      if( cpu_has_vmx )
> >      {
> > -        capabilities = (1U <<
> > XEN_DOMCTL_MONITOR_EVENT_WRITE_CTRLREG) |
> > -                       (1U <<
> > XEN_DOMCTL_MONITOR_EVENT_DEBUG_EXCEPTION) |
> > +        capabilities = (1U <<
> > XEN_DOMCTL_MONITOR_EVENT_DEBUG_EXCEPTION) |
> >                         (1U << XEN_DOMCTL_MONITOR_EVENT_CPUID) |
> >                         (1U << XEN_DOMCTL_MONITOR_EVENT_INTERRUPT)
> > |
> >                         (1U <<
> > XEN_DOMCTL_MONITOR_EVENT_EMUL_UNIMPLEMENTED);
> > @@ -92,7 +91,8 @@ static inline uint32_t
> > arch_monitor_get_capabilities(struct domain *d)
> >
> >      capabilities |= ((1U <<
> > XEN_DOMCTL_MONITOR_EVENT_GUEST_REQUEST) |
> >                      (1U <<
> > XEN_DOMCTL_MONITOR_EVENT_SOFTWARE_BREAKPOINT) |
> > -                    (1U << XEN_DOMCTL_MONITOR_EVENT_MOV_TO_MSR));
> > +                    (1U << XEN_DOMCTL_MONITOR_EVENT_MOV_TO_MSR) |
> > +                    (1U <<
> > XEN_DOMCTL_MONITOR_EVENT_WRITE_CTRLREG));
> >
> >      if ( hvm_funcs.set_descriptor_access_exiting )
> >          capabilities |= (1U <<
> > XEN_DOMCTL_MONITOR_EVENT_DESC_ACCESS);
> > --
> > 2.7.4

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