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[src/bouyer-xenpvh]: src/sys/arch/i386/i386 calling stipending() is only need...



details:   https://anonhg.NetBSD.org/src/rev/3d688093f2ba
branches:  bouyer-xenpvh
changeset: 982918:3d688093f2ba
user:      bouyer <bouyer%NetBSD.org@localhost>
date:      Sat Apr 11 12:01:42 2020 +0000

description:
calling stipending() is only needed in the PV case; in PVHVM
hypervisor_callback() will be called again as soon as we enable interrupts.

Use the PVHVM XENINTRSTUB for PV too; asjust Xdoreti as needed.
merge hypervisor_callback with hypervisor_pvhvm_callback. The reetrancy should
not be an issue, as we're already re-enabling events in
do_hupervisor_callback (that it, outside of the critical section).
We now can call Xdoreti in both cases.

diffstat:

 sys/arch/i386/i386/spl.S    |   14 ++---
 sys/arch/i386/i386/vector.S |  106 ++-----------------------------------------
 2 files changed, 11 insertions(+), 109 deletions(-)

diffs (223 lines):

diff -r b2b25cea5263 -r 3d688093f2ba sys/arch/i386/i386/spl.S
--- a/sys/arch/i386/i386/spl.S  Sat Apr 11 11:56:51 2020 +0000
+++ b/sys/arch/i386/i386/spl.S  Sat Apr 11 12:01:42 2020 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: spl.S,v 1.50.4.2 2020/04/11 10:11:31 bouyer Exp $      */
+/*     $NetBSD: spl.S,v 1.50.4.3 2020/04/11 12:01:42 bouyer Exp $      */
 
 /*
  * Copyright (c) 1998, 2007, 2008 The NetBSD Foundation, Inc.
@@ -30,7 +30,7 @@
  */
 
 #include <machine/asm.h>
-__KERNEL_RCSID(0, "$NetBSD: spl.S,v 1.50.4.2 2020/04/11 10:11:31 bouyer Exp $");
+__KERNEL_RCSID(0, "$NetBSD: spl.S,v 1.50.4.3 2020/04/11 12:01:42 bouyer Exp $");
 
 #include "opt_ddb.h"
 #include "opt_spldebug.h"
@@ -236,7 +236,7 @@
 #endif
 3:
        movl    %ebx,CPUVAR(ILEVEL)
-#ifdef XEN
+#ifdef XENPV
        STIC(%eax)
        jz 4f
        call    _C_LABEL(stipending)
@@ -260,7 +260,7 @@
 IDTVEC_END(spllower)
 
 /*
- * Handle return from interrupt after device handler finishes.
+ * Xdoreti: Handle return from interrupt after device handler finishes.
  *
  * Important registers:
  *   ebx - cpl to restore
@@ -270,10 +270,8 @@
  * called with interrupt disabled.
  */
 IDTVEC(doreti)
-#ifndef XENPV
        IDEPTH_DECR
        popl    %ebx                    /* get previous priority */
-#endif
 .Ldoreti_resume_stic:
        movl    $.Ldoreti_resume,%esi   /* address to resume loop at */
 .Ldoreti_resume:
@@ -292,7 +290,6 @@
 #endif /* XENPV */
 #endif /* defined(DEBUG) */
 
-#if !defined(XENPV)
        movl    %ebx,%eax
        movl    CPUVAR(IUNMASK)(,%eax,4),%eax
        andl    CPUVAR(IPENDING),%eax
@@ -301,7 +298,6 @@
        btrl    %eax,CPUVAR(IPENDING)
        movl    CPUVAR(ISOURCES)(,%eax, 4),%eax
        jmp     *IS_RESUME(%eax)
-#endif
 2:
 #if defined(XEN)
        movl    %ebx,%eax
@@ -340,7 +336,7 @@
        jnz     9f
        HANDLE_DEFERRED_FPU
 6:
-#ifdef XEN
+#ifdef XENPV
        STIC(%eax)
        jz      4f
        call    _C_LABEL(stipending)
diff -r b2b25cea5263 -r 3d688093f2ba sys/arch/i386/i386/vector.S
--- a/sys/arch/i386/i386/vector.S       Sat Apr 11 11:56:51 2020 +0000
+++ b/sys/arch/i386/i386/vector.S       Sat Apr 11 12:01:42 2020 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: vector.S,v 1.85.6.1 2020/04/10 14:42:00 bouyer Exp $   */
+/*     $NetBSD: vector.S,v 1.85.6.2 2020/04/11 12:01:42 bouyer Exp $   */
 
 /*
  * Copyright 2002 (c) Wasabi Systems, Inc.
@@ -65,7 +65,7 @@
  */
 
 #include <machine/asm.h>
-__KERNEL_RCSID(0, "$NetBSD: vector.S,v 1.85.6.1 2020/04/10 14:42:00 bouyer Exp $");
+__KERNEL_RCSID(0, "$NetBSD: vector.S,v 1.85.6.2 2020/04/11 12:01:42 bouyer Exp $");
 
 #include "opt_ddb.h"
 #include "opt_multiprocessor.h"
@@ -940,38 +940,6 @@
 #if defined(XEN)
 #define voidop(num)
 
-#ifdef XENPV
-#define        XENINTRSTUB(name, num, early_ack, late_ack, mask, unmask, level_mask) \
-IDTVEC(recurse_ ## name ## num)                                                ;\
-       INTR_RECURSE_HWFRAME                                            ;\
-       subl    $4,%esp                                                 ;\
-       pushl   $T_ASTFLT               /* trap # for doing ASTs */     ;\
-       INTRENTRY                                                       ;\
-       movl    $_C_LABEL(Xdoreti), %esi; /* we now have a trap frame, so loop using doreti instead */ ;\
-IDTVEC(resume_ ## name ## num)                                         \
-       movl    $IREENT_MAGIC,TF_ERR(%esp)                              ;\
-       pushl   %ebx                                                    ;\
-       movl    CPUVAR(XSOURCES) + (num) * 4,%ebp                       ;\
-       movl    $num,CPUVAR(ILEVEL)                                     ;\
-       IDEPTH_INCR /* leaves old %esp on stack */                      ;\
-       STI(%eax)                                                       ;\
-       movl    IS_HANDLERS(%ebp),%ebx                                  ;\
-6:                                                                     \
-       pushl   IH_ARG(%ebx)                                            ;\
-       call    *IH_FUN(%ebx)           /* call it */                   ;\
-       addl    $4,%esp                 /* toss the arg */              ;\
-       movl    IH_NEXT(%ebx),%ebx      /* next handler in chain */     ;\
-       testl   %ebx,%ebx                                               ;\
-       jnz     6b                                                      ;\
-                                                                       \
-       CLI(%eax)                                                       ;\
-       unmask(num)                     /* unmask it in hardware */     ;\
-       late_ack(num)                                                   ;\
-       IDEPTH_DECR                                                     ;\
-       popl    %ebx                                                    ;\
-       jmp     *%esi                   /* lower spl and do ASTs */     ;\
-
-#else /* XENPV */
 #define        XENINTRSTUB(name, num, early_ack, late_ack, mask, unmask, level_mask) \
 IDTVEC(recurse_ ## name ## num)                                                ;\
        INTR_RECURSE_HWFRAME                                            ;\
@@ -999,8 +967,6 @@
        late_ack(num)                                                   ;\
        jmp     _C_LABEL(Xdoreti)       /* lower spl and do ASTs */     ;\
 
-#endif /* XENPV */
-
 /*
  * Just unmasking the event isn't enough, we also need to
  * reassert the event pending bit if needed. For now just call
@@ -1110,80 +1076,20 @@
  * activation and restart the handler using the previous one.
  */
 ENTRY(hypervisor_callback)
-       pushl   $0                      /* dummy error code */
-       pushl   $T_ASTFLT
-       INTRENTRY
-       movl    TF_EIP(%esp),%eax
-       cmpl    $scrit,%eax
-       jb      11f
-       cmpl    $ecrit,%eax
-       jb      critical_region_fixup
-11:    pushl   CPUVAR(ILEVEL)
-       push    %esp
-       call    do_hypervisor_callback
-       add     $8,%esp
-       xorl    %eax,%eax
-       movb    TF_CS(%esp),%cl
-       test    $CHK_UPL,%cl            /* slow return to ring 2 or 3 */
-       je      safesti
-       movl    CPUVAR(ILEVEL),%ebx
-       jmp     doreti_checkast
-safesti:
-       movl    CPUVAR(VCPU),%esi
-       XEN_UNBLOCK_EVENTS(%esi)        /* reenable event callbacks */
-scrit: /**** START OF CRITICAL REGION ****/
-       XEN_TEST_PENDING(%esi)
-       jnz     14f             /* process more events if necessary... */
-       INTRFASTEXIT
-critiret:
-14:    XEN_BLOCK_EVENTS(%esi)
-       jmp     11b
-ecrit: /**** END OF CRITICAL REGION ****/
-/*
- * [How we do the fixup]. We want to merge the current stack frame with the
- * just-interrupted frame. How we do this depends on where in the critical
- * region the interrupted handler was executing, and so how many saved
- * registers are in each frame. We do this quickly using the lookup table
- * 'critical_fixup_table'. For each byte offset in the critical region, it
- * provides the number of bytes which have already been popped from the
- * interrupted stack frame.
- */
-critical_region_fixup:
-       cmpl    $(critiret-1),%eax      /* eip points to iret? */
-       jne     1f
-       movl    $(TF_PUSHSIZE+0x8),%eax
-       jmp     2f
-1:     xorl    %eax,%eax
-2:
-       /* %eax contains num bytes popped */
-       mov     %esp,%esi
-       add     %eax,%esi               /* %esi points at end of src region */
-       mov     %esp,%edi
-       add     $(TF_PUSHSIZE+0x8+0xC),%edi /* %edi points at end of dst region */
-       mov     %eax,%ecx
-       shr     $2,%ecx         /* convert words to bytes */
-       je      16f             /* skip loop if nothing to copy */
-15:    subl    $4,%esi         /* pre-decrementing copy loop */
-       subl    $4,%edi
-       movl    (%esi),%eax
-       movl    %eax,(%edi)
-       loop    15b
-16:    movl    %edi,%esp       /* final %edi is top of merged stack */
-       jmp     11b
-END(hypervisor_callback)
-
 IDTVEC(hypervisor_pvhvm_callback)      
        pushl   $0                      /* dummy error code */
        pushl   $T_ASTFLT
        INTRENTRY
+       pushl   CPUVAR(ILEVEL)
        push    %esp
        call    do_hypervisor_callback
        add     $4,%esp
-       push    CPUVAR(ILEVEL)
        IDEPTH_INCR
-       cli
+       CLI(%eax)
        jmp     _C_LABEL(Xdoreti)
 IDTVEC_END(hypervisor_pvhvm_callback)
+END(hypervisor_callback)
+
 #endif /* XEN */
 #ifdef XENPV   
 /*



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