4 files changed, 46 insertions, 61 deletions

diff --git a/arch/x86/xen/enlighten_hvm.c b/arch/x86/xen/enlighten_hvm.c
index 826898701045..19c1ff542387 100644
--- a/arch/x86/xen/enlighten_hvm.c
+++ b/arch/x86/xen/enlighten_hvm.c
@@ -65,6 +65,19 @@ static void __init xen_hvm_init_mem_mapping(void)
 {
 	early_memunmap(HYPERVISOR_shared_info, PAGE_SIZE);
 	HYPERVISOR_shared_info = __va(PFN_PHYS(shared_info_pfn));
+
+	/*
+	 * The virtual address of the shared_info page has changed, so
+	 * the vcpu_info pointer for VCPU 0 is now stale.
+	 *
+	 * The prepare_boot_cpu callback will re-initialize it via
+	 * xen_vcpu_setup, but we can't rely on that to be called for
+	 * old Xen versions (xen_have_vector_callback == 0).
+	 *
+	 * It is, in any case, bad to have a stale vcpu_info pointer
+	 * so reset it now.
+	 */
+	xen_vcpu_info_reset(0);
 }
 
 static void __init init_hvm_pv_info(void)
diff --git a/arch/x86/xen/enlighten_pv.c b/arch/x86/xen/enlighten_pv.c
index c36d23aa6c35..357969a3697c 100644
--- a/arch/x86/xen/enlighten_pv.c
+++ b/arch/x86/xen/enlighten_pv.c
@@ -421,45 +421,33 @@ static void xen_load_gdt(const struct desc_ptr *dtr)
 {
 	unsigned long va = dtr->address;
 	unsigned int size = dtr->size + 1;
-	unsigned pages = DIV_ROUND_UP(size, PAGE_SIZE);
-	unsigned long frames[pages];
-	int f;
-
-	/*
-	 * A GDT can be up to 64k in size, which corresponds to 8192
-	 * 8-byte entries, or 16 4k pages..
-	 */
+	unsigned long pfn, mfn;
+	int level;
+	pte_t *ptep;
+	void *virt;
 
-	BUG_ON(size > 65536);
+	/* @size should be at most GDT_SIZE which is smaller than PAGE_SIZE. */
+	BUG_ON(size > PAGE_SIZE);
 	BUG_ON(va & ~PAGE_MASK);
 
-	for (f = 0; va < dtr->address + size; va += PAGE_SIZE, f++) {
-		int level;
-		pte_t *ptep;
-		unsigned long pfn, mfn;
-		void *virt;
-
-		/*
-		 * The GDT is per-cpu and is in the percpu data area.
-		 * That can be virtually mapped, so we need to do a
-		 * page-walk to get the underlying MFN for the
-		 * hypercall.  The page can also be in the kernel's
-		 * linear range, so we need to RO that mapping too.
-		 */
-		ptep = lookup_address(va, &level);
-		BUG_ON(ptep == NULL);
-
-		pfn = pte_pfn(*ptep);
-		mfn = pfn_to_mfn(pfn);
-		virt = __va(PFN_PHYS(pfn));
+	/*
+	 * The GDT is per-cpu and is in the percpu data area.
+	 * That can be virtually mapped, so we need to do a
+	 * page-walk to get the underlying MFN for the
+	 * hypercall.  The page can also be in the kernel's
+	 * linear range, so we need to RO that mapping too.
+	 */
+	ptep = lookup_address(va, &level);
+	BUG_ON(ptep == NULL);
 
-		frames[f] = mfn;
+	pfn = pte_pfn(*ptep);
+	mfn = pfn_to_mfn(pfn);
+	virt = __va(PFN_PHYS(pfn));
 
-		make_lowmem_page_readonly((void *)va);
-		make_lowmem_page_readonly(virt);
-	}
+	make_lowmem_page_readonly((void *)va);
+	make_lowmem_page_readonly(virt);
 
-	if (HYPERVISOR_set_gdt(frames, size / sizeof(struct desc_struct)))
+	if (HYPERVISOR_set_gdt(&mfn, size / sizeof(struct desc_struct)))
 		BUG();
 }
 
@@ -470,34 +458,22 @@ static void __init xen_load_gdt_boot(const struct desc_ptr *dtr)
 {
 	unsigned long va = dtr->address;
 	unsigned int size = dtr->size + 1;
-	unsigned pages = DIV_ROUND_UP(size, PAGE_SIZE);
-	unsigned long frames[pages];
-	int f;
-
-	/*
-	 * A GDT can be up to 64k in size, which corresponds to 8192
-	 * 8-byte entries, or 16 4k pages..
-	 */
+	unsigned long pfn, mfn;
+	pte_t pte;
 
-	BUG_ON(size > 65536);
+	/* @size should be at most GDT_SIZE which is smaller than PAGE_SIZE. */
+	BUG_ON(size > PAGE_SIZE);
 	BUG_ON(va & ~PAGE_MASK);
 
-	for (f = 0; va < dtr->address + size; va += PAGE_SIZE, f++) {
-		pte_t pte;
-		unsigned long pfn, mfn;
+	pfn = virt_to_pfn(va);
+	mfn = pfn_to_mfn(pfn);
 
-		pfn = virt_to_pfn(va);
-		mfn = pfn_to_mfn(pfn);
+	pte = pfn_pte(pfn, PAGE_KERNEL_RO);
 
-		pte = pfn_pte(pfn, PAGE_KERNEL_RO);
-
-		if (HYPERVISOR_update_va_mapping((unsigned long)va, pte, 0))
-			BUG();
-
-		frames[f] = mfn;
-	}
+	if (HYPERVISOR_update_va_mapping((unsigned long)va, pte, 0))
+		BUG();
 
-	if (HYPERVISOR_set_gdt(frames, size / sizeof(struct desc_struct)))
+	if (HYPERVISOR_set_gdt(&mfn, size / sizeof(struct desc_struct)))
 		BUG();
 }
 
diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c
index d33e7dbe3129..2d76106788a3 100644
--- a/arch/x86/xen/mmu.c
+++ b/arch/x86/xen/mmu.c
@@ -42,13 +42,11 @@ xmaddr_t arbitrary_virt_to_machine(void *vaddr)
 }
 EXPORT_SYMBOL_GPL(arbitrary_virt_to_machine);
 
-static void xen_flush_tlb_all(void)
+static noinline void xen_flush_tlb_all(void)
 {
 	struct mmuext_op *op;
 	struct multicall_space mcs;
 
-	trace_xen_mmu_flush_tlb_all(0);
-
 	preempt_disable();
 
 	mcs = xen_mc_entry(sizeof(*op));
diff --git a/arch/x86/xen/mmu_pv.c b/arch/x86/xen/mmu_pv.c
index 486c0a34d00b..2c30cabfda90 100644
--- a/arch/x86/xen/mmu_pv.c
+++ b/arch/x86/xen/mmu_pv.c
@@ -1310,13 +1310,11 @@ unsigned long xen_read_cr2_direct(void)
 	return this_cpu_read(xen_vcpu_info.arch.cr2);
 }
 
-static void xen_flush_tlb(void)
+static noinline void xen_flush_tlb(void)
 {
 	struct mmuext_op *op;
 	struct multicall_space mcs;
 
-	trace_xen_mmu_flush_tlb(0);
-
 	preempt_disable();
 
 	mcs = xen_mc_entry(sizeof(*op));