Differential D30006 Diff 99020 sys/x86/xen/xen_arch_intr.c

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sys/x86/xen/xen_arch_intr.c

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	#include <sys/bus.h>			#include <sys/bus.h>
	#include <sys/malloc.h>			#include <sys/malloc.h>
	#include <sys/kernel.h>			#include <sys/kernel.h>
	#include <sys/limits.h>			#include <sys/limits.h>
	#include <sys/lock.h>			#include <sys/lock.h>
	#include <sys/mutex.h>			#include <sys/mutex.h>
	#include <sys/interrupt.h>			#include <sys/interrupt.h>
	#include <sys/pcpu.h>			#include <sys/pcpu.h>
				#include <sys/proc.h>
	#include <sys/smp.h>			#include <sys/smp.h>
	#include <sys/stddef.h>			#include <sys/stddef.h>

	#include <machine/intr_machdep.h>			#include <machine/intr_machdep.h>
	#include <x86/apicvar.h>			#include <x86/apicvar.h>

	#include <xen/xen-os.h>			#include <xen/xen-os.h>
	#include <xen/xen_intr.h>			#include <xen/xen_intr.h>
	#include <machine/xen/arch-intr.h>			#include <machine/xen/arch-intr.h>

	/*			/*
				* Pointers to the interrupt counters
				*/
				DPCPU_DEFINE_STATIC(u_long *, pintrcnt);

				/*
	* Lock for x86-related structures. Notably modifying			* Lock for x86-related structures. Notably modifying
	* xen_intr_auto_vector_count, and allocating interrupts require this lock be			* xen_intr_auto_vector_count, and allocating interrupts require this lock be
	* held.			* held.
	*/			*/
	static struct mtx xen_intr_x86_lock;			static struct mtx xen_intr_x86_lock;

	static u_int first_evtchn_irq;			static u_int first_evtchn_irq;

	static u_int xen_intr_auto_vector_count;			static u_int xen_intr_auto_vector_count;


				/*
				* Transition from assembly language, called from
				* sys/{amd64/amd64\|i386/i386}/apic_vector.[Ss]
				*/
				extern void xen_arch_intr_handle_upcall(struct trapframe *);
				void
				xen_arch_intr_handle_upcall(struct trapframe *trap_frame)
				{
				struct trapframe *old;

				/*
				* Disable preemption in order to always check and fire events
				* on the right vCPU
				*/
				critical_enter();

				++*DPCPU_GET(pintrcnt);

				ehem_freebsd_m5p.comAuthorUnsubmitted Done Inline Actions Approach #2 is here set `curthread->td_intr_frame = trap_frame;` (which is passed from assembly language). Then after the call set `curthread->td_intr_frame = NULL;`. I think this is right, but I would need a review... ehem_freebsd_m5p.com: Approach #2 is here set `curthread->td_intr_frame = trap_frame;` (which is passed from…
				mhorneUnsubmitted Done Inline Actions Yep, agreed that this is where you ought to set it. But as I said, you need to save and restore the previous value of `td_intr_frame`, not set it to `NULL`. mhorne: Yep, agreed that this is where you ought to set it. But as I said, you need to save and restore…
				ehem_freebsd_m5p.comAuthorUnsubmitted Done Inline Actions Okay, I can believe that. I cringe at how this means it will be saved both here and in `intr_event_handle()`, but that could well be correct. I was thinking setting it to `NULL` might be correct at this point the interrupt is returning and there shouldn't be further trap frames on the stack. ehem_freebsd_m5p.com: Okay, I can believe that. I cringe at how this means it will be saved both here and in…
				++curthread->td_intr_nesting_level;
				ehem_freebsd_m5p.comAuthorUnsubmitted Done Inline Actions I'm now guessing this (and the decrement 7 lines below) shouldn't be done. I'm not familiar enough with this to confidently make the call and need advice for whether this is correct. ehem_freebsd_m5p.com: I'm now guessing this (and the decrement 7 lines below) shouldn't be done. I'm not familiar…
				old = curthread->td_intr_frame;
				curthread->td_intr_frame = trap_frame;

				xen_intr_handle_upcall(NULL);

				curthread->td_intr_frame = old;
				--curthread->td_intr_nesting_level;

				if (xen_evtchn_needs_ack)
				lapic_eoi();
				ehem_freebsd_m5p.comAuthorUnsubmitted Done Inline Actions Note to reviewers (@royger) this is the really significant delta. Previously this would be done if `xen_intr_handle_upcall()` was invoked for the XenPCI code, but now this will only be invoked for the main Xen interrupt vector. This seems likely correct, but is worthy of reviewer attention. ehem_freebsd_m5p.com: Note to reviewers (@royger) this is the really significant delta. Previously this would be…

				critical_exit();
				}

				/**
				* Allocate and register a per-cpu Xen upcall interrupt counter.
				*
				* \param cpu The cpu for which to register this interrupt count.
				*/
				static void
				xen_intr_intrcnt_add(const u_int cpu)
				{
				char buf[MAXCOMLEN + 1];
				u_long **ppintrcnt;

				ppintrcnt = DPCPU_ID_PTR(cpu, pintrcnt);
				if (ppintrcnt != NULL)
				return;

				snprintf(buf, sizeof(buf), "cpu%d:xen", cpu);
				intrcnt_add(buf, ppintrcnt);
				}

				static void
				xen_intrcnt_init(void *dummy __unused)
				{
				unsigned int i;

				if (!xen_domain())
				return;

				/*
				* Register interrupt count manually as we aren't guaranteed to see a
				* call to xen_intr_assign_cpu() before our first interrupt.
				*/
				CPU_FOREACH(i)
				xen_intr_intrcnt_add(i);
				}
				SYSINIT(xen_intrcnt_init, SI_SUB_INTR, SI_ORDER_MIDDLE, xen_intrcnt_init, NULL);

	void			void
	xen_intr_alloc_irqs(void)			xen_intr_alloc_irqs(void)
	{			{

	if (num_io_irqs > UINT_MAX - NR_EVENT_CHANNELS)			if (num_io_irqs > UINT_MAX - NR_EVENT_CHANNELS)
	panic("IRQ allocation overflow (num_msi_irqs too high?)");			panic("IRQ allocation overflow (num_msi_irqs too high?)");
	first_evtchn_irq = num_io_irqs;			first_evtchn_irq = num_io_irqs;
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