libxc: rework BSP initialization

Place the calls to xc_vcpu_setcontext and the allocation of the hypercall
buffer into the arch-specific vcpu hooks. This is needed in order to
introduce a new builder, so x86 HVM guests can initialize the BSP using
XEN_DOMCTL_sethvmcontext instead of XEN_DOMCTL_setvcpucontext.

This patch should not introduce any functional change.

Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
Cc: Ian Jackson <ian.jackson@eu.citrix.com>
Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Cc: Ian Campbell <ian.campbell@citrix.com>
Cc: Wei Liu <wei.liu2@citrix.com>

tools/libxc/include/xc_dom.h

@@ -219,7 +219,7 @@ struct xc_dom_arch {
     /* arch-specific data structs setup */
     int (*start_info) (struct xc_dom_image * dom);
     int (*shared_info) (struct xc_dom_image * dom, void *shared_info);
-    int (*vcpu) (struct xc_dom_image * dom, void *vcpu_ctxt);
+    int (*vcpu) (struct xc_dom_image * dom);
     int (*bootearly) (struct xc_dom_image * dom);
     int (*bootlate) (struct xc_dom_image * dom);
 

tools/libxc/xc_dom_arm.c

@@ -119,9 +119,11 @@ static int shared_info_arm(struct xc_dom_image *dom, void *ptr)
 
 /* ------------------------------------------------------------------------ */
 
-static int vcpu_arm32(struct xc_dom_image *dom, void *ptr)
+static int vcpu_arm32(struct xc_dom_image *dom)
 {
-    vcpu_guest_context_t *ctxt = ptr;
+    vcpu_guest_context_any_t any_ctx;
+    vcpu_guest_context_t *ctxt = &any_ctx.c;
+    int rc;
 
     DOMPRINTF_CALLED(dom->xch);
 
@@ -154,12 +156,19 @@ static int vcpu_arm32(struct xc_dom_image *dom, void *ptr)
     DOMPRINTF("Initial state CPSR %#"PRIx32" PC %#"PRIx32,
            ctxt->user_regs.cpsr, ctxt->user_regs.pc32);
 
-    return 0;
+    rc = xc_vcpu_setcontext(dom->xch, dom->guest_domid, 0, &any_ctx);
+    if ( rc != 0 )
+        xc_dom_panic(dom->xch, XC_INTERNAL_ERROR,
+                     "%s: SETVCPUCONTEXT failed (rc=%d)", __func__, rc);
+
+    return rc;
 }
 
-static int vcpu_arm64(struct xc_dom_image *dom, void *ptr)
+static int vcpu_arm64(struct xc_dom_image *dom)
 {
-    vcpu_guest_context_t *ctxt = ptr;
+    vcpu_guest_context_any_t any_ctx;
+    vcpu_guest_context_t *ctxt = &any_ctx.c;
+    int rc;
 
     DOMPRINTF_CALLED(dom->xch);
     /* clear everything */
@@ -189,7 +198,12 @@ static int vcpu_arm64(struct xc_dom_image *dom, void *ptr)
     DOMPRINTF("Initial state CPSR %#"PRIx32" PC %#"PRIx64,
            ctxt->user_regs.cpsr, ctxt->user_regs.pc64);
 
-    return 0;
+    rc = xc_vcpu_setcontext(dom->xch, dom->guest_domid, 0, &any_ctx);
+    if ( rc != 0 )
+        xc_dom_panic(dom->xch, XC_INTERNAL_ERROR,
+                     "%s: SETVCPUCONTEXT failed (rc=%d)", __func__, rc);
+
+    return rc;
 }
 
 /* ------------------------------------------------------------------------ */

tools/libxc/xc_dom_boot.c

@@ -62,19 +62,6 @@ static int setup_hypercall_page(struct xc_dom_image *dom)
     return rc;
 }
 
-static int launch_vm(xc_interface *xch, domid_t domid,
-                     vcpu_guest_context_any_t *ctxt)
-{
-    int rc;
-
-    xc_dom_printf(xch, "%s: called, ctxt=%p", __FUNCTION__, ctxt);
-    rc = xc_vcpu_setcontext(xch, domid, 0, ctxt);
-    if ( rc != 0 )
-        xc_dom_panic(xch, XC_INTERNAL_ERROR,
-                     "%s: SETVCPUCONTEXT failed (rc=%d)", __FUNCTION__, rc);
-    return rc;
-}
-
 static int clear_page(struct xc_dom_image *dom, xen_pfn_t pfn)
 {
     xen_pfn_t dst;
@@ -197,14 +184,9 @@ void *xc_dom_boot_domU_map(struct xc_dom_image *dom, xen_pfn_t pfn,
 
 int xc_dom_boot_image(struct xc_dom_image *dom)
 {
-    DECLARE_HYPERCALL_BUFFER(vcpu_guest_context_any_t, ctxt);
     xc_dominfo_t info;
     int rc;
 
-    ctxt = xc_hypercall_buffer_alloc(dom->xch, ctxt, sizeof(*ctxt));
-    if ( ctxt == NULL )
-        return -1;
-
     DOMPRINTF_CALLED(dom->xch);
 
     /* misc stuff*/
@@ -259,13 +241,10 @@ int xc_dom_boot_image(struct xc_dom_image *dom)
         return rc;
 
     /* let the vm run */
-    memset(ctxt, 0, sizeof(*ctxt));
-    if ( (rc = dom->arch_hooks->vcpu(dom, ctxt)) != 0 )
+    if ( (rc = dom->arch_hooks->vcpu(dom)) != 0 )
         return rc;
     xc_dom_unmap_all(dom);
-    rc = launch_vm(dom->xch, dom->guest_domid, ctxt);
 
-    xc_hypercall_buffer_free(dom->xch, ctxt);
     return rc;
 }
 

tools/libxc/xc_dom_x86.c

@@ -584,10 +584,12 @@ static int shared_info_x86_64(struct xc_dom_image *dom, void *ptr)
 
 /* ------------------------------------------------------------------------ */
 
-static int vcpu_x86_32(struct xc_dom_image *dom, void *ptr)
+static int vcpu_x86_32(struct xc_dom_image *dom)
 {
-    vcpu_guest_context_x86_32_t *ctxt = ptr;
+    vcpu_guest_context_any_t any_ctx;
+    vcpu_guest_context_x86_32_t *ctxt = &any_ctx.x32;
     xen_pfn_t cr3_pfn;
+    int rc;
 
     DOMPRINTF_CALLED(dom->xch);
 
@@ -611,26 +613,33 @@ static int vcpu_x86_32(struct xc_dom_image *dom, void *ptr)
     DOMPRINTF("%s: cr3: pfn 0x%" PRIpfn " mfn 0x%" PRIpfn "",
               __FUNCTION__, dom->pgtables_seg.pfn, cr3_pfn);
 
-    if ( dom->pvh_enabled )
-        return 0;
+    if ( !dom->pvh_enabled )
+    {
+        ctxt->user_regs.ds = FLAT_KERNEL_DS_X86_32;
+        ctxt->user_regs.es = FLAT_KERNEL_DS_X86_32;
+        ctxt->user_regs.fs = FLAT_KERNEL_DS_X86_32;
+        ctxt->user_regs.gs = FLAT_KERNEL_DS_X86_32;
+        ctxt->user_regs.ss = FLAT_KERNEL_SS_X86_32;
+        ctxt->user_regs.cs = FLAT_KERNEL_CS_X86_32;
 
-    ctxt->user_regs.ds = FLAT_KERNEL_DS_X86_32;
-    ctxt->user_regs.es = FLAT_KERNEL_DS_X86_32;
-    ctxt->user_regs.fs = FLAT_KERNEL_DS_X86_32;
-    ctxt->user_regs.gs = FLAT_KERNEL_DS_X86_32;
-    ctxt->user_regs.ss = FLAT_KERNEL_SS_X86_32;
-    ctxt->user_regs.cs = FLAT_KERNEL_CS_X86_32;
+        ctxt->kernel_ss = ctxt->user_regs.ss;
+        ctxt->kernel_sp = ctxt->user_regs.esp;
+    }
 
-    ctxt->kernel_ss = ctxt->user_regs.ss;
-    ctxt->kernel_sp = ctxt->user_regs.esp;
+    rc = xc_vcpu_setcontext(dom->xch, dom->guest_domid, 0, &any_ctx);
+    if ( rc != 0 )
+        xc_dom_panic(dom->xch, XC_INTERNAL_ERROR,
+                     "%s: SETVCPUCONTEXT failed (rc=%d)", __func__, rc);
 
-    return 0;
+    return rc;
 }
 
-static int vcpu_x86_64(struct xc_dom_image *dom, void *ptr)
+static int vcpu_x86_64(struct xc_dom_image *dom)
 {
-    vcpu_guest_context_x86_64_t *ctxt = ptr;
+    vcpu_guest_context_any_t any_ctx;
+    vcpu_guest_context_x86_64_t *ctxt = &any_ctx.x64;
     xen_pfn_t cr3_pfn;
+    int rc;
 
     DOMPRINTF_CALLED(dom->xch);
 
@@ -663,7 +672,12 @@ static int vcpu_x86_64(struct xc_dom_image *dom, void *ptr)
     ctxt->kernel_ss = ctxt->user_regs.ss;
     ctxt->kernel_sp = ctxt->user_regs.esp;
 
-    return 0;
+    rc = xc_vcpu_setcontext(dom->xch, dom->guest_domid, 0, &any_ctx);
+    if ( rc != 0 )
+        xc_dom_panic(dom->xch, XC_INTERNAL_ERROR,
+                     "%s: SETVCPUCONTEXT failed (rc=%d)", __func__, rc);
+
+    return rc;
 }
 
 /* ------------------------------------------------------------------------ */