Re: [Xen-devel] [PATCH 3/7] xen/vm-events: Move monitor_domctl to common-side.

[Corneliu ZUZU <czuzu@xxxxxxxxxxxxxxx>]

On 2/8/2016 8:15 PM, Tamas K Lengyel wrote:

On Mon, Feb 8, 2016 at 9:57 AM, Corneliu ZUZU <czuzu@xxxxxxxxxxxxxxx> wrote:

+#if CONFIG_X86

Wouldn't it be safe to include these headers on ARM as well?

Â

+#include <public/vm_event.h>Â Â Â Â /* for VM_EVENT_X86_CR3 */
+#include <asm/hvm/hvm.h>Â Â Â Â Â Â /* for hvm_update_guest_cr, ... */
+#endif

It wouldn't break anything, but they are only necessary on X86, so why include them?

+
+Â Â if ( unlikely(mop->op != XEN_DOMCTL_MONITOR_OP_ENABLE &&
+Â Â Â Â Â Â Â Â Â mop->op != XEN_DOMCTL_MONITOR_OP_DISABLE) )
+Â Â {

Please make a switch on mop->op instead where the default case is to call arch_monitor_domctl. It would be a bit easier to follow.

+Â Â Â Â if ( XEN_DOMCTL_MONITOR_OP_GET_CAPABILITIES == mop->op )
+Â Â Â Â {
+Â Â Â Â Â Â mop->event = arch_monitor_get_capabilities(d);
+Â Â Â Â Â Â return 0;
+Â Â Â Â }
+

Noted, good point.

"proly"->probably?

Â

+Â Â Â Â /* The monitor op is proly handled on the arch-side. */
+Â Â Â Â if ( likely(arch_monitor_domctl_op(d, mop, &rc)) )
+Â Â Â Â Â Â return rc;

Yep, will "proly" change that, heh, just kidding. Noted :D.

Â

Empty line not needed. (*)

Noted.

So I don't particularly like this #if check here. IMHO this should be done in arch-specific function that you call from here that is just empty for ARM. It could be a static inline function as it's rather small.
Â

+#if CONFIG_X86

+Â Â Â Â if ( VM_EVENT_X86_CR3 == mop->u.mov_to_cr.index )
+Â Â Â Â {
+Â Â Â Â Â Â struct vcpu *v;
+Â Â Â Â Â Â /* Latches new CR3 mask through CR0 code. */
+Â Â Â Â Â Â for_each_vcpu ( d, v )
+Â Â Â Â Â Â Â Â hvm_update_guest_cr(v, 0);
+Â Â Â Â }
+#endif

I agree, but I was actually hoping to approach that in a future ARM-patch I'm going to send after this one.
On ARM, that part of code (where hypervisor CR trapping is enabled based on write_ctrlreg_enabled bits)
is done in another place (on the scheduling tail). I wanted to approach removing that #ifdef and finding maybe
a solution to do that similarly for X86. Would it be ok to leave this for that discussion? It would be simpler to illustrate
what I have in mind.

Looks good otherwise.

Thanks,

Tamas

Thanks,
Corneliu.

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