6 files changed, 33 insertions, 26 deletions

diff --git a/arch/x86/hyperv/hv_apic.c b/arch/x86/hyperv/hv_apic.c
index 1fbda2f94184..b21335e6a210 100644
--- a/arch/x86/hyperv/hv_apic.c
+++ b/arch/x86/hyperv/hv_apic.c
@@ -107,7 +107,6 @@ static bool cpu_is_self(int cpu)
 static bool __send_ipi_mask_ex(const struct cpumask *mask, int vector,
 		bool exclude_self)
 {
-	struct hv_send_ipi_ex **arg;
 	struct hv_send_ipi_ex *ipi_arg;
 	unsigned long flags;
 	int nr_bank = 0;
@@ -117,9 +116,8 @@ static bool __send_ipi_mask_ex(const struct cpumask *mask, int vector,
 		return false;
 
 	local_irq_save(flags);
-	arg = (struct hv_send_ipi_ex **)this_cpu_ptr(hyperv_pcpu_input_arg);
+	ipi_arg = *this_cpu_ptr(hyperv_pcpu_input_arg);
 
-	ipi_arg = *arg;
 	if (unlikely(!ipi_arg))
 		goto ipi_mask_ex_done;
 
diff --git a/arch/x86/hyperv/hv_init.c b/arch/x86/hyperv/hv_init.c
index 6c04b52f139b..953e280c07c3 100644
--- a/arch/x86/hyperv/hv_init.c
+++ b/arch/x86/hyperv/hv_init.c
@@ -14,6 +14,7 @@
 #include <asm/apic.h>
 #include <asm/desc.h>
 #include <asm/sev.h>
+#include <asm/ibt.h>
 #include <asm/hypervisor.h>
 #include <asm/hyperv-tlfs.h>
 #include <asm/mshyperv.h>
@@ -472,6 +473,26 @@ void __init hyperv_init(void)
 	}
 
 	/*
+	 * Some versions of Hyper-V that provide IBT in guest VMs have a bug
+	 * in that there's no ENDBR64 instruction at the entry to the
+	 * hypercall page. Because hypercalls are invoked via an indirect call
+	 * to the hypercall page, all hypercall attempts fail when IBT is
+	 * enabled, and Linux panics. For such buggy versions, disable IBT.
+	 *
+	 * Fixed versions of Hyper-V always provide ENDBR64 on the hypercall
+	 * page, so if future Linux kernel versions enable IBT for 32-bit
+	 * builds, additional hypercall page hackery will be required here
+	 * to provide an ENDBR32.
+	 */
+#ifdef CONFIG_X86_KERNEL_IBT
+	if (cpu_feature_enabled(X86_FEATURE_IBT) &&
+	    *(u32 *)hv_hypercall_pg != gen_endbr()) {
+		setup_clear_cpu_cap(X86_FEATURE_IBT);
+		pr_warn("Hyper-V: Disabling IBT because of Hyper-V bug\n");
+	}
+#endif
+
+	/*
 	 * hyperv_init() is called before LAPIC is initialized: see
 	 * apic_intr_mode_init() -> x86_platform.apic_post_init() and
 	 * apic_bsp_setup() -> setup_local_APIC(). The direct-mode STIMER
diff --git a/arch/x86/hyperv/hv_vtl.c b/arch/x86/hyperv/hv_vtl.c
index 85d38b9f3586..db5d2ea39fc0 100644
--- a/arch/x86/hyperv/hv_vtl.c
+++ b/arch/x86/hyperv/hv_vtl.c
@@ -25,6 +25,10 @@ void __init hv_vtl_init_platform(void)
 	x86_init.irqs.pre_vector_init = x86_init_noop;
 	x86_init.timers.timer_init = x86_init_noop;
 
+	/* Avoid searching for BIOS MP tables */
+	x86_init.mpparse.find_smp_config = x86_init_noop;
+	x86_init.mpparse.get_smp_config = x86_init_uint_noop;
+
 	x86_platform.get_wallclock = get_rtc_noop;
 	x86_platform.set_wallclock = set_rtc_noop;
 	x86_platform.get_nmi_reason = hv_get_nmi_reason;
diff --git a/arch/x86/hyperv/ivm.c b/arch/x86/hyperv/ivm.c
index 14f46ad2ca64..28be6df88063 100644
--- a/arch/x86/hyperv/ivm.c
+++ b/arch/x86/hyperv/ivm.c
@@ -247,7 +247,7 @@ EXPORT_SYMBOL_GPL(hv_ghcb_msr_read);
 static int hv_mark_gpa_visibility(u16 count, const u64 pfn[],
 			   enum hv_mem_host_visibility visibility)
 {
-	struct hv_gpa_range_for_visibility **input_pcpu, *input;
+	struct hv_gpa_range_for_visibility *input;
 	u16 pages_processed;
 	u64 hv_status;
 	unsigned long flags;
@@ -263,9 +263,8 @@ static int hv_mark_gpa_visibility(u16 count, const u64 pfn[],
 	}
 
 	local_irq_save(flags);
-	input_pcpu = (struct hv_gpa_range_for_visibility **)
-			this_cpu_ptr(hyperv_pcpu_input_arg);
-	input = *input_pcpu;
+	input = *this_cpu_ptr(hyperv_pcpu_input_arg);
+
 	if (unlikely(!input)) {
 		local_irq_restore(flags);
 		return -EINVAL;
diff --git a/arch/x86/hyperv/mmu.c b/arch/x86/hyperv/mmu.c
index 8460bd35e10c..1cc113200ff5 100644
--- a/arch/x86/hyperv/mmu.c
+++ b/arch/x86/hyperv/mmu.c
@@ -61,7 +61,6 @@ static void hyperv_flush_tlb_multi(const struct cpumask *cpus,
 				   const struct flush_tlb_info *info)
 {
 	int cpu, vcpu, gva_n, max_gvas;
-	struct hv_tlb_flush **flush_pcpu;
 	struct hv_tlb_flush *flush;
 	u64 status;
 	unsigned long flags;
@@ -74,10 +73,7 @@ static void hyperv_flush_tlb_multi(const struct cpumask *cpus,
 
 	local_irq_save(flags);
 
-	flush_pcpu = (struct hv_tlb_flush **)
-		     this_cpu_ptr(hyperv_pcpu_input_arg);
-
-	flush = *flush_pcpu;
+	flush = *this_cpu_ptr(hyperv_pcpu_input_arg);
 
 	if (unlikely(!flush)) {
 		local_irq_restore(flags);
@@ -178,17 +174,13 @@ static u64 hyperv_flush_tlb_others_ex(const struct cpumask *cpus,
 				      const struct flush_tlb_info *info)
 {
 	int nr_bank = 0, max_gvas, gva_n;
-	struct hv_tlb_flush_ex **flush_pcpu;
 	struct hv_tlb_flush_ex *flush;
 	u64 status;
 
 	if (!(ms_hyperv.hints & HV_X64_EX_PROCESSOR_MASKS_RECOMMENDED))
 		return HV_STATUS_INVALID_PARAMETER;
 
-	flush_pcpu = (struct hv_tlb_flush_ex **)
-		     this_cpu_ptr(hyperv_pcpu_input_arg);
-
-	flush = *flush_pcpu;
+	flush = *this_cpu_ptr(hyperv_pcpu_input_arg);
 
 	if (info->mm) {
 		/*
diff --git a/arch/x86/hyperv/nested.c b/arch/x86/hyperv/nested.c
index 5d70968c8538..9dc259fa322e 100644
--- a/arch/x86/hyperv/nested.c
+++ b/arch/x86/hyperv/nested.c
@@ -19,7 +19,6 @@
 
 int hyperv_flush_guest_mapping(u64 as)
 {
-	struct hv_guest_mapping_flush **flush_pcpu;
 	struct hv_guest_mapping_flush *flush;
 	u64 status;
 	unsigned long flags;
@@ -30,10 +29,7 @@ int hyperv_flush_guest_mapping(u64 as)
 
 	local_irq_save(flags);
 
-	flush_pcpu = (struct hv_guest_mapping_flush **)
-		this_cpu_ptr(hyperv_pcpu_input_arg);
-
-	flush = *flush_pcpu;
+	flush = *this_cpu_ptr(hyperv_pcpu_input_arg);
 
 	if (unlikely(!flush)) {
 		local_irq_restore(flags);
@@ -90,7 +86,6 @@ EXPORT_SYMBOL_GPL(hyperv_fill_flush_guest_mapping_list);
 int hyperv_flush_guest_mapping_range(u64 as,
 		hyperv_fill_flush_list_func fill_flush_list_func, void *data)
 {
-	struct hv_guest_mapping_flush_list **flush_pcpu;
 	struct hv_guest_mapping_flush_list *flush;
 	u64 status;
 	unsigned long flags;
@@ -102,10 +97,8 @@ int hyperv_flush_guest_mapping_range(u64 as,
 
 	local_irq_save(flags);
 
-	flush_pcpu = (struct hv_guest_mapping_flush_list **)
-		this_cpu_ptr(hyperv_pcpu_input_arg);
+	flush = *this_cpu_ptr(hyperv_pcpu_input_arg);
 
-	flush = *flush_pcpu;
 	if (unlikely(!flush)) {
 		local_irq_restore(flags);
 		goto fault;