On Thu, Nov 06, 2025 at 07:12:36PM +0100, hshoexer wrote:
> Hi,
>
> On Thu, Nov 06, 2025 at 12:18:27PM -0500, Dave Voutila wrote:
> > hshoexer <hshoexer@yerbouti.franken.de> writes:
> >
> > > Hi,
> > >
> > > I'd like to simplify the implementation of amd64's
> > > wbinvd_on_all_cpus_acked() by using cpu_xcall(9).
> > >
> > > The diff below rewrites wbinvd_on_all_cpus_acked() accordingly.
> > >
> > > The required xcall glue code for amd64 is from this [1] mail by
> > > dlg@.  If the wbinvd_on_all_cpus_acked() is ok, I'm fine with
> > > splitting this diff.
> > >
> > > Thoughts?
> > >
> >
> > I believe dlg@ has some changes he may not have shared that are not in
> > tree that shuffle a bit of how things split across MI/MD.
> >
> > Given we're post-release, I think it's a good time to start that
> > conversation again.
>
> excellent! The wbinvd rewrite is quite simple.  I'd be happy to use
> it to test drive cpu_xcall.
>

yeah, the xcall stuff has to get finished first then we can look at
this diff (wbinvd)

> > > Take care,
> > > HJ.
> > >
> > > [1] https://marc.info/?l=openbsd-tech&m=175246988124240
> > > -----------------------------------------------------------------
> > > commit 394bdebb36b1c9699343896fa2091cd1f52be6e3
> > > Author: hshoexer <hshoexer@yerbouti.franken.de>
> > > Date:   Thu Nov 6 15:01:52 2025 +0100
> > >
> > >     rewrite wbinvd_on_all_cpus_acked() using cpu_xcall(9)
> > >
> > >     change includes required amd64 glue code by dlg@ as seen here:
> > >     https://marc.info/?l=openbsd-tech&m=175246988124240
> > >
> > > diff --git a/sys/arch/amd64/amd64/cpu.c b/sys/arch/amd64/amd64/cpu.c
> > > index 5baf179a398..93f554cb652 100644
> > > --- a/sys/arch/amd64/amd64/cpu.c
> > > +++ b/sys/arch/amd64/amd64/cpu.c
> > > @@ -79,6 +79,7 @@
> > >  #include <sys/memrange.h>
> > >  #include <sys/atomic.h>
> > >  #include <sys/user.h>
> > > +#include <sys/xcall.h>
> > >
> > >  #include <uvm/uvm_extern.h>
> > >
> > > @@ -642,6 +643,8 @@ cpu_attach(struct device *parent, struct device *self, void *aux)
> > >  #endif
> > >
> > >  #if defined(MULTIPROCESSOR)
> > > +	cpu_xcall_establish(ci);
> > > +
> > >  	/*
> > >  	 * Allocate UPAGES contiguous pages for the idle PCB and stack.
> > >  	 */
> > > @@ -1475,44 +1478,23 @@ wbinvd_on_all_cpus(void)
> > >  	return 0;
> > >  }
> > >
> > > -volatile long wbinvd_wait __attribute__((section(".kudata")));
> > > +static void
> > > +xcwbinvd(void *arg)
> > > +{
> > > +	wbinvd();
> > > +}
> > >
> > >  void
> > >  wbinvd_on_all_cpus_acked(void)
> > >  {
> > > -	struct cpu_info *ci, *self = curcpu();;
> > > -	CPU_INFO_ITERATOR cii;
> > > -	long wait = 0;
> > > -	u_int64_t mask = 0;
> > > -	int s;
> > > +	struct cpu_info		*ci;
> > > +	CPU_INFO_ITERATOR	 cii;
> > >
> > >  	CPU_INFO_FOREACH(cii, ci) {
> > > -		if (ci == self || !(ci->ci_flags & CPUF_RUNNING))
> > > +		if (!(ci->ci_flags & CPUF_RUNNING))
> > >  			continue;
> > > -		mask |= (1ULL << ci->ci_cpuid);
> > > -		wait++;
> > > -	}
> > > -
> > > -	if (wait > 0) {
> > > -		s = splvm();
> > > -		while (atomic_cas_ulong(&wbinvd_wait, 0 , wait) != 0) {
> > > -			while (wbinvd_wait != 0)
> > > -				CPU_BUSY_CYCLE();
> > > -		}
> > > -
> > > -		CPU_INFO_FOREACH(cii, ci) {
> > > -			if ((mask & (1ULL << ci->ci_cpuid)) == 0)
> > > -				continue;
> > > -			if (x86_fast_ipi(ci, LAPIC_IPI_WBINVD) != 0)
> > > -				panic("%s: ipi failed", __func__);
> > > -		}
> > > -		splx(s);
> > > +		cpu_xcall_sync(ci, xcwbinvd, NULL, "xcwbinvd");
> > >  	}
> > > -
> > > -	wbinvd();
> > > -
> > > -	while (wbinvd_wait != 0)
> > > -		CPU_BUSY_CYCLE();
> > >  }
> > >  #endif /* MULTIPROCESSOR */
> > >
> > > diff --git a/sys/arch/amd64/amd64/ipifuncs.c b/sys/arch/amd64/amd64/ipifuncs.c
> > > index 482fc9eebb4..8a068278fc2 100644
> > > --- a/sys/arch/amd64/amd64/ipifuncs.c
> > > +++ b/sys/arch/amd64/amd64/ipifuncs.c
> > > @@ -108,6 +108,7 @@ void (*ipifunc[X86_NIPI])(struct cpu_info *) =
> > >  	NULL,
> > >  #endif
> > >  	x86_64_ipi_wbinvd,
> > > +	cpu_xcall_dispatch,
> > >  };
> > >
> > >  void
> > > diff --git a/sys/arch/amd64/amd64/lapic.c b/sys/arch/amd64/amd64/lapic.c
> > > index f7fdb81ccca..ccf743303f2 100644
> > > --- a/sys/arch/amd64/amd64/lapic.c
> > > +++ b/sys/arch/amd64/amd64/lapic.c
> > > @@ -364,8 +364,6 @@ lapic_boot_init(paddr_t lapic_base)
> > >  		idt_vec_set(LAPIC_IPI_INVLPG, Xipi_invlpg_pcid);
> > >  		idt_vec_set(LAPIC_IPI_INVLRANGE, Xipi_invlrange_pcid);
> > >  	}
> > > -	idt_allocmap[LAPIC_IPI_WBINVD] = 1;
> > > -	idt_vec_set(LAPIC_IPI_WBINVD, Xipi_wbinvd);
> > >  #if NVMM > 0
> > >  	idt_allocmap[LAPIC_IPI_INVEPT] = 1;
> > >  	idt_vec_set(LAPIC_IPI_INVEPT, Xipi_invept);
> > > diff --git a/sys/arch/amd64/amd64/vector.S b/sys/arch/amd64/amd64/vector.S
> > > index 8b82db6b4f6..c531c9f827c 100644
> > > --- a/sys/arch/amd64/amd64/vector.S
> > > +++ b/sys/arch/amd64/amd64/vector.S
> > > @@ -816,17 +816,6 @@ IDTVEC(ipi_invlrange_pcid)
> > >  	iretq
> > >  END(Xipi_invlrange_pcid)
> > >
> > > -IDTVEC(ipi_wbinvd)
> > > -	ioapic_asm_ack()
> > > -
> > > -	wbinvd
> > > -
> > > -	lock
> > > -	decq	wbinvd_wait
> > > -
> > > -	iretq
> > > -END(Xipi_wbinvd)
> > > -
> > >  #endif /* MULTIPROCESSOR */
> > >
> > >  	/*
> > > diff --git a/sys/arch/amd64/conf/files.amd64 b/sys/arch/amd64/conf/files.amd64
> > > index 630de36a01d..38d5796f650 100644
> > > --- a/sys/arch/amd64/conf/files.amd64
> > > +++ b/sys/arch/amd64/conf/files.amd64
> > > @@ -95,7 +95,7 @@ file	arch/amd64/amd64/mpbios.c		mpbios needs-flag
> > >  file	arch/amd64/amd64/mpbios_intr_fixup.c	mpbios & pci
> > >
> > >  define	cpu {[apid = -1]}
> > > -device	cpu
> > > +device	cpu: xcall
> > >  attach	cpu at mainbus
> > >  file	arch/amd64/amd64/cpu.c	cpu
> > >
> > > diff --git a/sys/arch/amd64/include/cpu.h b/sys/arch/amd64/include/cpu.h
> > > index b125f1c4d50..f3b8ec80d96 100644
> > > --- a/sys/arch/amd64/include/cpu.h
> > > +++ b/sys/arch/amd64/include/cpu.h
> > > @@ -53,6 +53,7 @@
> > >  #include <sys/sched.h>
> > >  #include <sys/sensors.h>
> > >  #include <sys/srp.h>
> > > +#include <sys/xcall.h>
> > >  #include <uvm/uvm_percpu.h>
> > >
> > >  #ifdef _KERNEL
> > > @@ -215,6 +216,7 @@ struct cpu_info {
> > >
> > >  #ifdef MULTIPROCESSOR
> > >  	struct srp_hazard	ci_srp_hazards[SRP_HAZARD_NUM];
> > > +	struct xcall_cpu	ci_xcall;
> > >  #define __HAVE_UVM_PERCPU
> > >  	struct uvm_pmr_cache	ci_uvm;		/* [o] page cache */
> > >  #endif
> > > diff --git a/sys/arch/amd64/include/i82489var.h b/sys/arch/amd64/include/i82489var.h
> > > index 561efa3fbd7..95dfff5173d 100644
> > > --- a/sys/arch/amd64/include/i82489var.h
> > > +++ b/sys/arch/amd64/include/i82489var.h
> > > @@ -72,8 +72,7 @@ extern void Xresume_lapic_ipi(void);
> > >  #define LAPIC_IPI_INVLTLB			(LAPIC_IPI_OFFSET + 0)
> > >  #define LAPIC_IPI_INVLPG			(LAPIC_IPI_OFFSET + 1)
> > >  #define LAPIC_IPI_INVLRANGE			(LAPIC_IPI_OFFSET + 2)
> > > -#define LAPIC_IPI_WBINVD			(LAPIC_IPI_OFFSET + 3)
> > > -#define LAPIC_IPI_INVEPT			(LAPIC_IPI_OFFSET + 4)
> > > +#define LAPIC_IPI_INVEPT			(LAPIC_IPI_OFFSET + 3)
> > >
> > >  extern void Xipi_invltlb(void);
> > >  extern void Xipi_invltlb_pcid(void);
> > > @@ -81,7 +80,6 @@ extern void Xipi_invlpg(void);
> > >  extern void Xipi_invlpg_pcid(void);
> > >  extern void Xipi_invlrange(void);
> > >  extern void Xipi_invlrange_pcid(void);
> > > -extern void Xipi_wbinvd(void);
> > >  #if NVMM > 0
> > >  extern void Xipi_invept(void);
> > >  #endif /* NVMM > 0 */
> > > diff --git a/sys/arch/amd64/include/intr.h b/sys/arch/amd64/include/intr.h
> > > index c0e12824c2d..ffdff36ca38 100644
> > > --- a/sys/arch/amd64/include/intr.h
> > > +++ b/sys/arch/amd64/include/intr.h
> > > @@ -222,7 +222,9 @@ void x86_ipi_handler(void);
> > >  void x86_setperf_ipi(struct cpu_info *);
> > >
> > >  extern void (*ipifunc[X86_NIPI])(struct cpu_info *);
> > > -#endif
> > > +
> > > +#define cpu_xcall_ipi(_ci) x86_send_ipi((_ci), X86_IPI_XCALL)
> > > +#endif /* MULTIPROCESSOR */
> > >
> > >  #endif /* !_LOCORE */
> > >
> > > diff --git a/sys/arch/amd64/include/intrdefs.h b/sys/arch/amd64/include/intrdefs.h
> > > index 048d0202b88..69238b46155 100644
> > > --- a/sys/arch/amd64/include/intrdefs.h
> > > +++ b/sys/arch/amd64/include/intrdefs.h
> > > @@ -85,8 +85,9 @@
> > >  #define X86_IPI_START_VMM		0x00000100
> > >  #define X86_IPI_STOP_VMM		0x00000200
> > >  #define X86_IPI_WBINVD			0x00000400
> > > +#define X86_IPI_XCALL			0x00000800
> > >
> > > -#define X86_NIPI			12
> > > +#define X86_NIPI			13
> > >
> > >  #define IREENT_MAGIC	0x18041969
> > >
> > > diff --git a/sys/conf/files b/sys/conf/files
> > > index 59df8c6fd1b..1e00c25cb6c 100644
> > > --- a/sys/conf/files
> > > +++ b/sys/conf/files
> > > @@ -751,7 +751,7 @@ file kern/kern_uuid.c
> > >  file kern/kern_watchdog.c		!small_kernel
> > >  file kern/kern_task.c
> > >  file kern/kern_srp.c
> > > -file kern/kern_xcall.c			xcall			needs-flag
> > > +file kern/kern_xcall.c			xcall
> > >  file kern/kern_xxx.c
> > >  file kern/sched_bsd.c
> > >  file kern/subr_autoconf.c
> >
>