Patch "x86/kvm/vmx: Simplify segment_base()" has been added to the 4.9-stable tree

This is a note to let you know that I've just added the patch titled

x86/kvm/vmx: Simplify segment_base()

to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
x86-kvm-vmx-simplify-segment_base.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Andy Lutomirski <[email protected]>
Date: Mon, 20 Feb 2017 08:56:12 -0800
Subject: x86/kvm/vmx: Simplify segment_base()
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From: Andy Lutomirski <[email protected]>

commit 8c2e41f7ae1234c192ef497472ad306227c77c03 upstream.

Use actual pointer types for pointers (instead of unsigned long) and replace hardcoded constants with the appropriate self-documenting macros.

The function is still a bit messy, but this seems a lot better than before to me.

This is mostly borrowed from a patch by Thomas Garnier.

---
 arch/x86/kvm/vmx.c |   19 +++++++------------
 1 file changed, 7 insertions(+), 12 deletions(-)

@@ -2030,28 +2030,23 @@ static unsigned long segment_base(u16 se
 {
 	struct desc_ptr *gdt = this_cpu_ptr(&host_gdt);
 	struct desc_struct *d;
-	unsigned long table_base;
+	struct desc_struct *table;
 	unsigned long v;
 
-	if (!(selector & ~3))
+	if (!(selector & ~SEGMENT_RPL_MASK))
 		return 0;
 
-	table_base = gdt->address;
+	table = (struct desc_struct *)gdt->address;
 
-	if (selector & 4) {           /* from ldt */
+	if ((selector & SEGMENT_TI_MASK) == SEGMENT_LDT) {
 		u16 ldt_selector = kvm_read_ldt();
 
-		if (!(ldt_selector & ~3))
+		if (!(ldt_selector & ~SEGMENT_RPL_MASK))
 			return 0;
 
-		table_base = segment_base(ldt_selector);
+		table = (struct desc_struct *)segment_base(ldt_selector);
 	}
-	d = (struct desc_struct *)(table_base + (selector & ~7));
-	v = get_desc_base(d);
-#ifdef CONFIG_X86_64
-       if (d->s == 0 && (d->type == 2 || d->type == 9 || d->type == 11))
-               v |= ((unsigned long)((struct ldttss_desc64 *)d)->base3) << 32;
-#endif
+	v = get_desc_base(&table[selector >> 3]);
 	return v;
 }
 

Patches currently in stable-queue which might be from [email protected] are

queue-4.9/x86-mm-refactor-flush_tlb_mm_range-to-merge-local-and-remote-cases.patch queue-4.9/x86-mm-pass-flush_tlb_info-to-flush_tlb_others-etc.patch queue-4.9/x86-mm-rework-lazy-tlb-to-track-the-actual-loaded-mm.patch queue-4.9/x86-mm-kvm-teach-kvm-s-vmx-code-that-cr3-isn-t-a-constant.patch queue-4.9/x86-mm-use-new-merged-flush-logic-in-arch_tlbbatch_flush.patch queue-4.9/x86-kvm-vmx-simplify-segment_base.patch queue-4.9/x86-entry-unwind-create-stack-frames-for-saved-interrupt-registers.patch queue-4.9/x86-mm-reduce-indentation-in-flush_tlb_func.patch queue-4.9/x86-mm-remove-the-up-asm-tlbflush.h-code-always-use-the-formerly-smp-code.patch queue-4.9/x86-mm-reimplement-flush_tlb_page-using-flush_tlb_mm_range.patch queue-4.9/mm-x86-mm-make-the-batched-unmap-tlb-flush-api-more-generic.patch queue-4.9/x86-kvm-vmx-defer-tr-reload-after-vm-exit.patch queue-4.9/x86-mm-change-the-leave_mm-condition-for-local-tlb-flushes.patch queue-4.9/x86-mm-be-more-consistent-wrt-page_shift-vs-page_size-in-tlb-flush-code.patch