Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/arch/x86/hyperv/hv_init.c b/arch/x86/hyperv/hv_init.c
index 20c876c..2db3972 100644
--- a/arch/x86/hyperv/hv_init.c
+++ b/arch/x86/hyperv/hv_init.c
@@ -1,22 +1,13 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * X86 specific Hyper-V initialization code.
  *
  * Copyright (C) 2016, Microsoft, Inc.
  *
  * Author : K. Y. Srinivasan <kys@microsoft.com>
- *
- * This program is free software; you can redistribute it and/or modify it
- * under the terms of the GNU General Public License version 2 as published
- * by the Free Software Foundation.
- *
- * This program is distributed in the hope that it will be useful, but
- * WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
- * NON INFRINGEMENT.  See the GNU General Public License for more
- * details.
- *
  */
 
+#include <linux/efi.h>
 #include <linux/types.h>
 #include <asm/apic.h>
 #include <asm/desc.h>
@@ -26,64 +17,13 @@
 #include <linux/version.h>
 #include <linux/vmalloc.h>
 #include <linux/mm.h>
-#include <linux/clockchips.h>
 #include <linux/hyperv.h>
 #include <linux/slab.h>
 #include <linux/cpuhotplug.h>
-
-#ifdef CONFIG_HYPERV_TSCPAGE
-
-static struct ms_hyperv_tsc_page *tsc_pg;
-
-struct ms_hyperv_tsc_page *hv_get_tsc_page(void)
-{
-	return tsc_pg;
-}
-EXPORT_SYMBOL_GPL(hv_get_tsc_page);
-
-static u64 read_hv_clock_tsc(struct clocksource *arg)
-{
-	u64 current_tick = hv_read_tsc_page(tsc_pg);
-
-	if (current_tick == U64_MAX)
-		rdmsrl(HV_X64_MSR_TIME_REF_COUNT, current_tick);
-
-	return current_tick;
-}
-
-static struct clocksource hyperv_cs_tsc = {
-		.name		= "hyperv_clocksource_tsc_page",
-		.rating		= 400,
-		.read		= read_hv_clock_tsc,
-		.mask		= CLOCKSOURCE_MASK(64),
-		.flags		= CLOCK_SOURCE_IS_CONTINUOUS,
-};
-#endif
-
-static u64 read_hv_clock_msr(struct clocksource *arg)
-{
-	u64 current_tick;
-	/*
-	 * Read the partition counter to get the current tick count. This count
-	 * is set to 0 when the partition is created and is incremented in
-	 * 100 nanosecond units.
-	 */
-	rdmsrl(HV_X64_MSR_TIME_REF_COUNT, current_tick);
-	return current_tick;
-}
-
-static struct clocksource hyperv_cs_msr = {
-	.name		= "hyperv_clocksource_msr",
-	.rating		= 400,
-	.read		= read_hv_clock_msr,
-	.mask		= CLOCKSOURCE_MASK(64),
-	.flags		= CLOCK_SOURCE_IS_CONTINUOUS,
-};
+#include <clocksource/hyperv_timer.h>
 
 void *hv_hypercall_pg;
 EXPORT_SYMBOL_GPL(hv_hypercall_pg);
-struct clocksource *hyperv_cs;
-EXPORT_SYMBOL_GPL(hyperv_cs);
 
 u32 *hv_vp_index;
 EXPORT_SYMBOL_GPL(hv_vp_index);
@@ -95,15 +35,34 @@
 EXPORT_SYMBOL_GPL(hyperv_pcpu_input_arg);
 
 u32 hv_max_vp_index;
+EXPORT_SYMBOL_GPL(hv_max_vp_index);
+
+void *hv_alloc_hyperv_page(void)
+{
+	BUILD_BUG_ON(PAGE_SIZE != HV_HYP_PAGE_SIZE);
+
+	return (void *)__get_free_page(GFP_KERNEL);
+}
+EXPORT_SYMBOL_GPL(hv_alloc_hyperv_page);
+
+void hv_free_hyperv_page(unsigned long addr)
+{
+	free_page(addr);
+}
+EXPORT_SYMBOL_GPL(hv_free_hyperv_page);
 
 static int hv_cpu_init(unsigned int cpu)
 {
 	u64 msr_vp_index;
 	struct hv_vp_assist_page **hvp = &hv_vp_assist_page[smp_processor_id()];
 	void **input_arg;
+	struct page *pg;
 
 	input_arg = (void **)this_cpu_ptr(hyperv_pcpu_input_arg);
-	*input_arg = page_address(alloc_page(GFP_KERNEL));
+	pg = alloc_page(GFP_KERNEL);
+	if (unlikely(!pg))
+		return -ENOMEM;
+	*input_arg = page_address(pg);
 
 	hv_get_vp_index(msr_vp_index);
 
@@ -115,8 +74,17 @@
 	if (!hv_vp_assist_page)
 		return 0;
 
-	if (!*hvp)
-		*hvp = __vmalloc(PAGE_SIZE, GFP_KERNEL, PAGE_KERNEL);
+	/*
+	 * The VP ASSIST PAGE is an "overlay" page (see Hyper-V TLFS's Section
+	 * 5.2.1 "GPA Overlay Pages"). Here it must be zeroed out to make sure
+	 * we always write the EOI MSR in hv_apic_eoi_write() *after* the
+	 * EOI optimization is disabled in hv_cpu_die(), otherwise a CPU may
+	 * not be stopped in the case of CPU offlining and the VM will hang.
+	 */
+	if (!*hvp) {
+		*hvp = __vmalloc(PAGE_SIZE, GFP_KERNEL | __GFP_ZERO,
+				 PAGE_KERNEL);
+	}
 
 	if (*hvp) {
 		u64 val;
@@ -253,6 +221,22 @@
 	return 0;
 }
 
+static int __init hv_pci_init(void)
+{
+	int gen2vm = efi_enabled(EFI_BOOT);
+
+	/*
+	 * For Generation-2 VM, we exit from pci_arch_init() by returning 0.
+	 * The purpose is to suppress the harmless warning:
+	 * "PCI: Fatal: No config space access function found"
+	 */
+	if (gen2vm)
+		return 0;
+
+	/* For Generation-1 VM, we'll proceed in pci_arch_init().  */
+	return 1;
+}
+
 /*
  * This function is to be invoked early in the boot sequence after the
  * hypervisor has been detected.
@@ -329,41 +313,7 @@
 
 	hv_apic_init();
 
-	/*
-	 * Register Hyper-V specific clocksource.
-	 */
-#ifdef CONFIG_HYPERV_TSCPAGE
-	if (ms_hyperv.features & HV_MSR_REFERENCE_TSC_AVAILABLE) {
-		union hv_x64_msr_hypercall_contents tsc_msr;
-
-		tsc_pg = __vmalloc(PAGE_SIZE, GFP_KERNEL, PAGE_KERNEL);
-		if (!tsc_pg)
-			goto register_msr_cs;
-
-		hyperv_cs = &hyperv_cs_tsc;
-
-		rdmsrl(HV_X64_MSR_REFERENCE_TSC, tsc_msr.as_uint64);
-
-		tsc_msr.enable = 1;
-		tsc_msr.guest_physical_address = vmalloc_to_pfn(tsc_pg);
-
-		wrmsrl(HV_X64_MSR_REFERENCE_TSC, tsc_msr.as_uint64);
-
-		hyperv_cs_tsc.archdata.vclock_mode = VCLOCK_HVCLOCK;
-
-		clocksource_register_hz(&hyperv_cs_tsc, NSEC_PER_SEC/100);
-		return;
-	}
-register_msr_cs:
-#endif
-	/*
-	 * For 32 bit guests just use the MSR based mechanism for reading
-	 * the partition counter.
-	 */
-
-	hyperv_cs = &hyperv_cs_msr;
-	if (ms_hyperv.features & HV_MSR_TIME_REF_COUNT_AVAILABLE)
-		clocksource_register_hz(&hyperv_cs_msr, NSEC_PER_SEC/100);
+	x86_init.pci.arch_init = hv_pci_init;
 
 	return;
 
@@ -387,6 +337,13 @@
 	/* Reset our OS id */
 	wrmsrl(HV_X64_MSR_GUEST_OS_ID, 0);
 
+	/*
+	 * Reset hypercall page reference before reset the page,
+	 * let hypercall operations fail safely rather than
+	 * panic the kernel for using invalid hypercall page
+	 */
+	hv_hypercall_pg = NULL;
+
 	/* Reset the hypercall page */
 	hypercall_msr.as_uint64 = 0;
 	wrmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);