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Commit fa612137 authored by Xiao Guangrong's avatar Xiao Guangrong Committed by Paolo Bonzini
Browse files

KVM: MTRR: simplify kvm_mtrr_get_guest_memory_type 



mtrr_for_each_mem_type() is ready now, use it to simplify
kvm_mtrr_get_guest_memory_type()

Signed-off-by: default avatarXiao Guangrong <guangrong.xiao@linux.intel.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent f571c097

arch/x86/kvm/mtrr.c

+16 −48
Original line number Diff line number Diff line
@@ -600,61 +600,23 @@ static void mtrr_lookup_next(struct mtrr_iter *iter) 
u8 kvm_mtrr_get_guest_memory_type(struct kvm_vcpu *vcpu, gfn_t gfn)

{

	struct kvm_mtrr *mtrr_state = &vcpu->arch.mtrr_state;

	u64 base, mask, start;

	int i, num_var_ranges, type;

	struct mtrr_iter iter;

	u64 start, end;

	int type = -1;

	const int wt_wb_mask = (1 << MTRR_TYPE_WRBACK)

			       | (1 << MTRR_TYPE_WRTHROUGH);



	start = gfn_to_gpa(gfn);

	num_var_ranges = KVM_NR_VAR_MTRR;

	type = -1;



	/* MTRR is completely disabled, use UC for all of physical memory. */

	if (!mtrr_is_enabled(mtrr_state))

		return MTRR_TYPE_UNCACHABLE;



	/* Look in fixed ranges. Just return the type as per start */

	if (fixed_mtrr_is_enabled(mtrr_state) && (start < 0x100000)) {

		int idx;



		if (start < 0x80000) {

			idx = 0;

			idx += (start >> 16);

			return mtrr_state->fixed_ranges[idx];

		} else if (start < 0xC0000) {

			idx = 1 * 8;

			idx += ((start - 0x80000) >> 14);

			return mtrr_state->fixed_ranges[idx];

		} else if (start < 0x1000000) {

			idx = 3 * 8;

			idx += ((start - 0xC0000) >> 12);

			return mtrr_state->fixed_ranges[idx];

		}

	}



	/*

	 * Look in variable ranges

	 * Look of multiple ranges matching this address and pick type

	 * as per MTRR precedence

	 */

	for (i = 0; i < num_var_ranges; ++i) {

		int curr_type;



		if (!(mtrr_state->var_ranges[i].mask & (1 << 11)))

			continue;

	end = start + PAGE_SIZE;



		base = mtrr_state->var_ranges[i].base & PAGE_MASK;

		mask = mtrr_state->var_ranges[i].mask & PAGE_MASK;



		if ((start & mask) != (base & mask))

			continue;

	mtrr_for_each_mem_type(&iter, mtrr_state, start, end) {

		int curr_type = iter.mem_type;



		/*

		 * Please refer to Intel SDM Volume 3: 11.11.4.1 MTRR

		 * Precedences.

		 */



		curr_type = mtrr_state->var_ranges[i].base & 0xff;

		if (type == -1) {

			type = curr_type;

			continue;
@@ -694,9 +656,15 @@ u8 kvm_mtrr_get_guest_memory_type(struct kvm_vcpu *vcpu, gfn_t gfn) 
		return MTRR_TYPE_WRBACK;

	}



	if (type != -1)

	/* It is not covered by MTRRs. */

	if (iter.partial_map) {

		/*

		 * We just check one page, partially covered by MTRRs is

		 * impossible.

		 */

		WARN_ON(type != -1);

		type = mtrr_default_type(mtrr_state);

	}

	return type;



	return mtrr_default_type(mtrr_state);

}

EXPORT_SYMBOL_GPL(kvm_mtrr_get_guest_memory_type);