From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Juergen Gross <jgross@suse.com>
Date: Thu, 9 Nov 2017 14:27:35 +0100
Subject: [PATCH] x86/virt, x86/platform: Merge 'struct x86_hyper' into 'struct
 x86_platform' and 'struct x86_init'
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CVE-2017-5754

Instead of x86_hyper being either NULL on bare metal or a pointer to a
struct hypervisor_x86 in case of the kernel running as a guest merge
the struct into x86_platform and x86_init.

This will remove the need for wrappers making it hard to find out what
is being called. With dummy functions added for all callbacks testing
for a NULL function pointer can be removed, too.

Suggested-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Juergen Gross <jgross@suse.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: akataria@vmware.com
Cc: boris.ostrovsky@oracle.com
Cc: devel@linuxdriverproject.org
Cc: haiyangz@microsoft.com
Cc: kvm@vger.kernel.org
Cc: kys@microsoft.com
Cc: pbonzini@redhat.com
Cc: rkrcmar@redhat.com
Cc: rusty@rustcorp.com.au
Cc: sthemmin@microsoft.com
Cc: virtualization@lists.linux-foundation.org
Cc: xen-devel@lists.xenproject.org
Link: http://lkml.kernel.org/r/20171109132739.23465-2-jgross@suse.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
(cherry picked from commit f72e38e8ec8869ac0ba5a75d7d2f897d98a1454e)
Signed-off-by: Andy Whitcroft <apw@canonical.com>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>
(cherry picked from commit 2d0b017b38623bca666acbcb5ab251315845fa55)
Signed-off-by: Fabian Grünbichler <f.gruenbichler@proxmox.com>
---
 arch/x86/include/asm/hypervisor.h | 25 ++++--------------
 arch/x86/include/asm/x86_init.h   | 24 +++++++++++++++++
 include/linux/hypervisor.h        |  8 ++++--
 arch/x86/kernel/apic/apic.c       |  2 +-
 arch/x86/kernel/cpu/hypervisor.c  | 54 +++++++++++++++++++--------------------
 arch/x86/kernel/cpu/mshyperv.c    |  2 +-
 arch/x86/kernel/cpu/vmware.c      |  4 +--
 arch/x86/kernel/kvm.c             |  2 +-
 arch/x86/kernel/x86_init.c        |  9 +++++++
 arch/x86/mm/init.c                |  2 +-
 arch/x86/xen/enlighten_hvm.c      |  8 +++---
 arch/x86/xen/enlighten_pv.c       |  2 +-
 12 files changed, 81 insertions(+), 61 deletions(-)

diff --git a/arch/x86/include/asm/hypervisor.h b/arch/x86/include/asm/hypervisor.h
index 0ead9dbb9130..0eca7239a7aa 100644
--- a/arch/x86/include/asm/hypervisor.h
+++ b/arch/x86/include/asm/hypervisor.h
@@ -23,6 +23,7 @@
 #ifdef CONFIG_HYPERVISOR_GUEST
 
 #include <asm/kvm_para.h>
+#include <asm/x86_init.h>
 #include <asm/xen/hypervisor.h>
 
 /*
@@ -35,17 +36,11 @@ struct hypervisor_x86 {
 	/* Detection routine */
 	uint32_t	(*detect)(void);
 
-	/* Platform setup (run once per boot) */
-	void		(*init_platform)(void);
+	/* init time callbacks */
+	struct x86_hyper_init init;
 
-	/* X2APIC detection (run once per boot) */
-	bool		(*x2apic_available)(void);
-
-	/* pin current vcpu to specified physical cpu (run rarely) */
-	void		(*pin_vcpu)(int);
-
-	/* called during init_mem_mapping() to setup early mappings. */
-	void		(*init_mem_mapping)(void);
+	/* runtime callbacks */
+	struct x86_hyper_runtime runtime;
 };
 
 extern const struct hypervisor_x86 *x86_hyper;
@@ -58,17 +53,7 @@ extern const struct hypervisor_x86 x86_hyper_xen_hvm;
 extern const struct hypervisor_x86 x86_hyper_kvm;
 
 extern void init_hypervisor_platform(void);
-extern bool hypervisor_x2apic_available(void);
-extern void hypervisor_pin_vcpu(int cpu);
-
-static inline void hypervisor_init_mem_mapping(void)
-{
-	if (x86_hyper && x86_hyper->init_mem_mapping)
-		x86_hyper->init_mem_mapping();
-}
 #else
 static inline void init_hypervisor_platform(void) { }
-static inline bool hypervisor_x2apic_available(void) { return false; }
-static inline void hypervisor_init_mem_mapping(void) { }
 #endif /* CONFIG_HYPERVISOR_GUEST */
 #endif /* _ASM_X86_HYPERVISOR_H */
diff --git a/arch/x86/include/asm/x86_init.h b/arch/x86/include/asm/x86_init.h
index 7ba7e90a9ad6..4d95e5a13c0b 100644
--- a/arch/x86/include/asm/x86_init.h
+++ b/arch/x86/include/asm/x86_init.h
@@ -113,6 +113,18 @@ struct x86_init_pci {
 	void (*fixup_irqs)(void);
 };
 
+/**
+ * struct x86_hyper_init - x86 hypervisor init functions
+ * @init_platform:		platform setup
+ * @x2apic_available:		X2APIC detection
+ * @init_mem_mapping:		setup early mappings during init_mem_mapping()
+ */
+struct x86_hyper_init {
+	void (*init_platform)(void);
+	bool (*x2apic_available)(void);
+	void (*init_mem_mapping)(void);
+};
+
 /**
  * struct x86_init_ops - functions for platform specific setup
  *
@@ -126,6 +138,7 @@ struct x86_init_ops {
 	struct x86_init_timers		timers;
 	struct x86_init_iommu		iommu;
 	struct x86_init_pci		pci;
+	struct x86_hyper_init		hyper;
 };
 
 /**
@@ -198,6 +211,15 @@ struct x86_legacy_features {
 	struct x86_legacy_devices devices;
 };
 
+/**
+ * struct x86_hyper_runtime - x86 hypervisor specific runtime callbacks
+ *
+ * @pin_vcpu:		pin current vcpu to specified physical cpu (run rarely)
+ */
+struct x86_hyper_runtime {
+	void (*pin_vcpu)(int cpu);
+};
+
 /**
  * struct x86_platform_ops - platform specific runtime functions
  * @calibrate_cpu:		calibrate CPU
@@ -217,6 +239,7 @@ struct x86_legacy_features {
  * 				possible in x86_early_init_platform_quirks() by
  * 				only using the current x86_hardware_subarch
  * 				semantics.
+ * @hyper:			x86 hypervisor specific runtime callbacks
  */
 struct x86_platform_ops {
 	unsigned long (*calibrate_cpu)(void);
@@ -232,6 +255,7 @@ struct x86_platform_ops {
 	void (*apic_post_init)(void);
 	struct x86_legacy_features legacy;
 	void (*set_legacy_features)(void);
+	struct x86_hyper_runtime hyper;
 };
 
 struct pci_dev;
diff --git a/include/linux/hypervisor.h b/include/linux/hypervisor.h
index 3fa5ef2b3759..35e170ca87a8 100644
--- a/include/linux/hypervisor.h
+++ b/include/linux/hypervisor.h
@@ -6,8 +6,12 @@
  *		Juergen Gross <jgross@suse.com>
  */
 
-#ifdef CONFIG_HYPERVISOR_GUEST
-#include <asm/hypervisor.h>
+#ifdef CONFIG_X86
+#include <asm/x86_init.h>
+static inline void hypervisor_pin_vcpu(int cpu)
+{
+	x86_platform.hyper.pin_vcpu(cpu);
+}
 #else
 static inline void hypervisor_pin_vcpu(int cpu)
 {
diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c
index 4a7f962b53ff..bb63c1350524 100644
--- a/arch/x86/kernel/apic/apic.c
+++ b/arch/x86/kernel/apic/apic.c
@@ -1666,7 +1666,7 @@ static __init void try_to_enable_x2apic(int remap_mode)
 		 * under KVM
 		 */
 		if (max_physical_apicid > 255 ||
-		    !hypervisor_x2apic_available()) {
+		    !x86_init.hyper.x2apic_available()) {
 			pr_info("x2apic: IRQ remapping doesn't support X2APIC mode\n");
 			x2apic_disable();
 			return;
diff --git a/arch/x86/kernel/cpu/hypervisor.c b/arch/x86/kernel/cpu/hypervisor.c
index 4fa90006ac68..22226c1bf092 100644
--- a/arch/x86/kernel/cpu/hypervisor.c
+++ b/arch/x86/kernel/cpu/hypervisor.c
@@ -44,51 +44,49 @@ static const __initconst struct hypervisor_x86 * const hypervisors[] =
 const struct hypervisor_x86 *x86_hyper;
 EXPORT_SYMBOL(x86_hyper);
 
-static inline void __init
+static inline const struct hypervisor_x86 * __init
 detect_hypervisor_vendor(void)
 {
-	const struct hypervisor_x86 *h, * const *p;
+	const struct hypervisor_x86 *h = NULL, * const *p;
 	uint32_t pri, max_pri = 0;
 
 	for (p = hypervisors; p < hypervisors + ARRAY_SIZE(hypervisors); p++) {
-		h = *p;
-		pri = h->detect();
-		if (pri != 0 && pri > max_pri) {
+		pri = (*p)->detect();
+		if (pri > max_pri) {
 			max_pri = pri;
-			x86_hyper = h;
+			h = *p;
 		}
 	}
 
-	if (max_pri)
-		pr_info("Hypervisor detected: %s\n", x86_hyper->name);
+	if (h)
+		pr_info("Hypervisor detected: %s\n", h->name);
+
+	return h;
 }
 
-void __init init_hypervisor_platform(void)
+static void __init copy_array(const void *src, void *target, unsigned int size)
 {
+	unsigned int i, n = size / sizeof(void *);
+	const void * const *from = (const void * const *)src;
+	const void **to = (const void **)target;
 
-	detect_hypervisor_vendor();
-
-	if (!x86_hyper)
-		return;
-
-	if (x86_hyper->init_platform)
-		x86_hyper->init_platform();
+	for (i = 0; i < n; i++)
+		if (from[i])
+			to[i] = from[i];
 }
 
-bool __init hypervisor_x2apic_available(void)
+void __init init_hypervisor_platform(void)
 {
-	return x86_hyper                   &&
-	       x86_hyper->x2apic_available &&
-	       x86_hyper->x2apic_available();
-}
+	const struct hypervisor_x86 *h;
 
-void hypervisor_pin_vcpu(int cpu)
-{
-	if (!x86_hyper)
+	h = detect_hypervisor_vendor();
+
+	if (!h)
 		return;
 
-	if (x86_hyper->pin_vcpu)
-		x86_hyper->pin_vcpu(cpu);
-	else
-		WARN_ONCE(1, "vcpu pinning requested but not supported!\n");
+	copy_array(&h->init, &x86_init.hyper, sizeof(h->init));
+	copy_array(&h->runtime, &x86_platform.hyper, sizeof(h->runtime));
+
+	x86_hyper = h;
+	x86_init.hyper.init_platform();
 }
diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c
index 70e717fccdd6..9707e431da27 100644
--- a/arch/x86/kernel/cpu/mshyperv.c
+++ b/arch/x86/kernel/cpu/mshyperv.c
@@ -255,6 +255,6 @@ static void __init ms_hyperv_init_platform(void)
 const __refconst struct hypervisor_x86 x86_hyper_ms_hyperv = {
 	.name			= "Microsoft HyperV",
 	.detect			= ms_hyperv_platform,
-	.init_platform		= ms_hyperv_init_platform,
+	.init.init_platform	= ms_hyperv_init_platform,
 };
 EXPORT_SYMBOL(x86_hyper_ms_hyperv);
diff --git a/arch/x86/kernel/cpu/vmware.c b/arch/x86/kernel/cpu/vmware.c
index 40ed26852ebd..4804c1d063c8 100644
--- a/arch/x86/kernel/cpu/vmware.c
+++ b/arch/x86/kernel/cpu/vmware.c
@@ -208,7 +208,7 @@ static bool __init vmware_legacy_x2apic_available(void)
 const __refconst struct hypervisor_x86 x86_hyper_vmware = {
 	.name			= "VMware",
 	.detect			= vmware_platform,
-	.init_platform		= vmware_platform_setup,
-	.x2apic_available	= vmware_legacy_x2apic_available,
+	.init.init_platform	= vmware_platform_setup,
+	.init.x2apic_available	= vmware_legacy_x2apic_available,
 };
 EXPORT_SYMBOL(x86_hyper_vmware);
diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c
index 9e3798b00e40..54e373bfeab9 100644
--- a/arch/x86/kernel/kvm.c
+++ b/arch/x86/kernel/kvm.c
@@ -547,7 +547,7 @@ static uint32_t __init kvm_detect(void)
 const struct hypervisor_x86 x86_hyper_kvm __refconst = {
 	.name			= "KVM",
 	.detect			= kvm_detect,
-	.x2apic_available	= kvm_para_available,
+	.init.x2apic_available	= kvm_para_available,
 };
 EXPORT_SYMBOL_GPL(x86_hyper_kvm);
 
diff --git a/arch/x86/kernel/x86_init.c b/arch/x86/kernel/x86_init.c
index a088b2c47f73..5b2d10c1973a 100644
--- a/arch/x86/kernel/x86_init.c
+++ b/arch/x86/kernel/x86_init.c
@@ -28,6 +28,8 @@ void x86_init_noop(void) { }
 void __init x86_init_uint_noop(unsigned int unused) { }
 int __init iommu_init_noop(void) { return 0; }
 void iommu_shutdown_noop(void) { }
+bool __init bool_x86_init_noop(void) { return false; }
+void x86_op_int_noop(int cpu) { }
 
 /*
  * The platform setup functions are preset with the default functions
@@ -81,6 +83,12 @@ struct x86_init_ops x86_init __initdata = {
 		.init_irq		= x86_default_pci_init_irq,
 		.fixup_irqs		= x86_default_pci_fixup_irqs,
 	},
+
+	.hyper = {
+		.init_platform		= x86_init_noop,
+		.x2apic_available	= bool_x86_init_noop,
+		.init_mem_mapping	= x86_init_noop,
+	},
 };
 
 struct x86_cpuinit_ops x86_cpuinit = {
@@ -101,6 +109,7 @@ struct x86_platform_ops x86_platform __ro_after_init = {
 	.get_nmi_reason			= default_get_nmi_reason,
 	.save_sched_clock_state 	= tsc_save_sched_clock_state,
 	.restore_sched_clock_state 	= tsc_restore_sched_clock_state,
+	.hyper.pin_vcpu			= x86_op_int_noop,
 };
 
 EXPORT_SYMBOL_GPL(x86_platform);
diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c
index af5c1ed21d43..a22c2b95e513 100644
--- a/arch/x86/mm/init.c
+++ b/arch/x86/mm/init.c
@@ -671,7 +671,7 @@ void __init init_mem_mapping(void)
 	load_cr3(swapper_pg_dir);
 	__flush_tlb_all();
 
-	hypervisor_init_mem_mapping();
+	x86_init.hyper.init_mem_mapping();
 
 	early_memtest(0, max_pfn_mapped << PAGE_SHIFT);
 }
diff --git a/arch/x86/xen/enlighten_hvm.c b/arch/x86/xen/enlighten_hvm.c
index de503c225ae1..7b1622089f96 100644
--- a/arch/x86/xen/enlighten_hvm.c
+++ b/arch/x86/xen/enlighten_hvm.c
@@ -229,9 +229,9 @@ static uint32_t __init xen_platform_hvm(void)
 const struct hypervisor_x86 x86_hyper_xen_hvm = {
 	.name                   = "Xen HVM",
 	.detect                 = xen_platform_hvm,
-	.init_platform          = xen_hvm_guest_init,
-	.pin_vcpu               = xen_pin_vcpu,
-	.x2apic_available       = xen_x2apic_para_available,
-	.init_mem_mapping	= xen_hvm_init_mem_mapping,
+	.init.init_platform     = xen_hvm_guest_init,
+	.init.x2apic_available  = xen_x2apic_para_available,
+	.init.init_mem_mapping	= xen_hvm_init_mem_mapping,
+	.runtime.pin_vcpu       = xen_pin_vcpu,
 };
 EXPORT_SYMBOL(x86_hyper_xen_hvm);
diff --git a/arch/x86/xen/enlighten_pv.c b/arch/x86/xen/enlighten_pv.c
index e7b213047724..4110fc9e5ee9 100644
--- a/arch/x86/xen/enlighten_pv.c
+++ b/arch/x86/xen/enlighten_pv.c
@@ -1461,6 +1461,6 @@ static uint32_t __init xen_platform_pv(void)
 const struct hypervisor_x86 x86_hyper_xen_pv = {
 	.name                   = "Xen PV",
 	.detect                 = xen_platform_pv,
-	.pin_vcpu               = xen_pin_vcpu,
+	.runtime.pin_vcpu       = xen_pin_vcpu,
 };
 EXPORT_SYMBOL(x86_hyper_xen_pv);
-- 
2.14.2

