KVM: x86: Do not set access bit on accessed segments (e2cefa74) · Commits · 戴 / test

When segment is loaded, the segment access bit is set unconditionally. In fact, it should be set conditionally, based on whether the segment had the accessed bit set before. In addition, it can improve performance. Signed-off-by:

Nadav Amit <namit@cs.technion.ac.il> Signed-off-by:

Paolo Bonzini <pbonzini@redhat.com>

arch/x86/kvm/emulate.c

+7 −4

Original line number	Diff line number	Diff line
		@@ -1618,10 +1618,13 @@ static int __load_segment_descriptor(struct x86_emulate_ctxt *ctxt,

		if (seg_desc.s) {
		/* mark segment as accessed */
		if (!(seg_desc.type & 1)) {
		seg_desc.type \|= 1;
		ret = write_segment_descriptor(ctxt, selector, &seg_desc);
		ret = write_segment_descriptor(ctxt, selector,
		&seg_desc);
		if (ret != X86EMUL_CONTINUE)
		return ret;
		}
		} else if (ctxt->mode == X86EMUL_MODE_PROT64) {
		ret = ctxt->ops->read_std(ctxt, desc_addr+8, &base3,
		sizeof(base3), &ctxt->exception);

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