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Re: [Xen-devel] [PATCH v2 01/10] x86/HVM: Introduce struct hvm_pi_ops
On 01/10/2017 03:24 PM, Jan Beulich wrote:
On 10.01.17 at 07:51, <Suravee.Suthikulpanit@xxxxxxx> wrote:
On 01/05/2017 10:51 PM, Jan Beulich wrote:
On 31.12.16 at 06:45, <suravee.suthikulpanit@xxxxxxx> wrote:
--- a/xen/include/asm-x86/hvm/domain.h
+++ b/xen/include/asm-x86/hvm/domain.h
@@ -72,6 +72,67 @@ struct hvm_ioreq_server {
bool_t bufioreq_atomic;
};
+struct hvm_pi_ops {
+ /*
+ * To handle posted interrupts correctly, we need to set the following
+ * state:
+ *
+ * * The PI notification vector (NV)
+ * * The PI notification destination processor (NDST)
+ * * The PI "suppress notification" bit (SN)
+ * * The vcpu pi "blocked" list
+ *
+ * If a VM is currently running, we want the PI delivered to the guest vcpu
+ * on the proper pcpu (NDST = v->processor, SN clear).
+ *
+ * If the vm is blocked, we want the PI delivered to Xen so that it can
+ * wake it up (SN clear, NV = pi_wakeup_vector, vcpu on block list).
+ *
+ * If the VM is currently either preempted or offline (i.e., not running
+ * because of some reason other than blocking waiting for an interrupt),
+ * there's nothing Xen can do -- we want the interrupt pending bit set in
[....]
+ *
+ * For transition C, we add a new arch hook, arch_vcpu_block(), which is
+ * called from vcpu_block() and vcpu_do_poll().
+ *
+ * For transition D, rather than add an extra arch hook on vcpu_wake, we
+ * add a hook on the vmentry path which checks to see if either of the two
+ * actions need to be taken.
+ *
+ * These hooks only need to be called when the domain in question actually
+ * has a physical device assigned to it, so we set and clear the callbacks
+ * as appropriate when device assignment changes.
+ */
+ void (*vcpu_block) (struct vcpu *);
+ void (*pi_switch_from) (struct vcpu *v);
+ void (*pi_switch_to) (struct vcpu *v);
+ void (*pi_do_resume) (struct vcpu *v);
+};
While the hooks (as said, with the pi_ prefixes dropped) are
certainly fine to move here, the comment is extremely VMX
centric, and hence doesn't fit in this file. It either needs to be
generalized, or it should remain in VMX specific code, perhaps
with a referral to it added here.
I see. I will move the comment into arch/x86/hvm/vmx/vmx.c close to
where these hooks are implemented.
So you see no way of generalizing it? (I confess I didn't look closely
enough yet at the [dis]similarities between VMX/VT-d PI and AVIC
to be able to easily tell myself.)
I would need to look at VMX/VT-d PI also. But my impression is it's
quite different.
S
Jan
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