1 files changed, 102 insertions, 6 deletions

diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c
index a01ca255b0c6..53282dc7d5ac 100644
--- a/arch/x86/xen/enlighten.c
+++ b/arch/x86/xen/enlighten.c
@@ -1,10 +1,8 @@
 // SPDX-License-Identifier: GPL-2.0
 
-#ifdef CONFIG_XEN_BALLOON_MEMORY_HOTPLUG
-#include <linux/memblock.h>
-#endif
 #include <linux/console.h>
 #include <linux/cpu.h>
+#include <linux/instrumentation.h>
 #include <linux/kexec.h>
 #include <linux/memblock.h>
 #include <linux/slab.h>
@@ -23,10 +21,9 @@
 #include <asm/setup.h>
 
 #include "xen-ops.h"
-#include "smp.h"
-#include "pmu.h"
 
-EXPORT_SYMBOL_GPL(hypercall_page);
+DEFINE_STATIC_CALL(xen_hypercall, xen_hypercall_hvm);
+EXPORT_STATIC_CALL_TRAMP(xen_hypercall);
 
 /*
  * Pointer to the xen_vcpu_info structure or
@@ -73,6 +70,65 @@ EXPORT_SYMBOL(xen_start_flags);
  */
 struct shared_info *HYPERVISOR_shared_info = &xen_dummy_shared_info;
 
+/* Number of pages released from the initial allocation. */
+unsigned long xen_released_pages;
+
+static __ref void xen_get_vendor(void)
+{
+	init_cpu_devs();
+	cpu_detect(&boot_cpu_data);
+	get_cpu_vendor(&boot_cpu_data);
+}
+
+void xen_hypercall_setfunc(void)
+{
+	if (static_call_query(xen_hypercall) != xen_hypercall_hvm)
+		return;
+
+	if ((boot_cpu_data.x86_vendor == X86_VENDOR_AMD ||
+	     boot_cpu_data.x86_vendor == X86_VENDOR_HYGON))
+		static_call_update(xen_hypercall, xen_hypercall_amd);
+	else
+		static_call_update(xen_hypercall, xen_hypercall_intel);
+}
+
+/*
+ * Evaluate processor vendor in order to select the correct hypercall
+ * function for HVM/PVH guests.
+ * Might be called very early in boot before vendor has been set by
+ * early_cpu_init().
+ */
+noinstr void *__xen_hypercall_setfunc(void)
+{
+	void (*func)(void);
+
+	/*
+	 * Note that __xen_hypercall_setfunc() is noinstr only due to a nasty
+	 * dependency chain: it is being called via the xen_hypercall static
+	 * call when running as a PVH or HVM guest. Hypercalls need to be
+	 * noinstr due to PV guests using hypercalls in noinstr code. So we
+	 * can safely tag the function body as "instrumentation ok", since
+	 * the PV guest requirement is not of interest here (xen_get_vendor()
+	 * calls noinstr functions, and static_call_update_early() might do
+	 * so, too).
+	 */
+	instrumentation_begin();
+
+	xen_get_vendor();
+
+	if ((boot_cpu_data.x86_vendor == X86_VENDOR_AMD ||
+	     boot_cpu_data.x86_vendor == X86_VENDOR_HYGON))
+		func = xen_hypercall_amd;
+	else
+		func = xen_hypercall_intel;
+
+	static_call_update_early(xen_hypercall, func);
+
+	instrumentation_end();
+
+	return func;
+}
+
 static int xen_cpu_up_online(unsigned int cpu)
 {
 	xen_init_lock_cpu(cpu);
@@ -382,3 +438,43 @@ void __init xen_add_extra_mem(unsigned long start_pfn, unsigned long n_pfns)
 
 	memblock_reserve(PFN_PHYS(start_pfn), PFN_PHYS(n_pfns));
 }
+
+#ifdef CONFIG_XEN_UNPOPULATED_ALLOC
+int __init arch_xen_unpopulated_init(struct resource **res)
+{
+	unsigned int i;
+
+	if (!xen_domain())
+		return -ENODEV;
+
+	/* Must be set strictly before calling xen_free_unpopulated_pages(). */
+	*res = &iomem_resource;
+
+	/*
+	 * Initialize with pages from the extra memory regions (see
+	 * arch/x86/xen/setup.c).
+	 */
+	for (i = 0; i < XEN_EXTRA_MEM_MAX_REGIONS; i++) {
+		unsigned int j;
+
+		for (j = 0; j < xen_extra_mem[i].n_pfns; j++) {
+			struct page *pg =
+				pfn_to_page(xen_extra_mem[i].start_pfn + j);
+
+			xen_free_unpopulated_pages(1, &pg);
+		}
+
+		/*
+		 * Account for the region being in the physmap but unpopulated.
+		 * The value in xen_released_pages is used by the balloon
+		 * driver to know how much of the physmap is unpopulated and
+		 * set an accurate initial memory target.
+		 */
+		xen_released_pages += xen_extra_mem[i].n_pfns;
+		/* Zero so region is not also added to the balloon driver. */
+		xen_extra_mem[i].n_pfns = 0;
+	}
+
+	return 0;
+}
+#endif