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Commit 10dc331f authored by Xiao Guangrong's avatar Xiao Guangrong Committed by Paolo Bonzini
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KVM: MTRR: fix memory type handling if MTRR is completely disabled 



Currently code uses default memory type if MTRR is fully disabled,
fix it by using UC instead.

Signed-off-by: default avatarXiao Guangrong <guangrong.xiao@intel.com>
Tested-by: default avatarAlex Williamson <alex.williamson@redhat.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent c5dfd654

arch/x86/kvm/mtrr.c

+20 −1
Original line number Diff line number Diff line
@@ -120,6 +120,16 @@ static u8 mtrr_default_type(struct kvm_mtrr *mtrr_state) 
	return mtrr_state->deftype & IA32_MTRR_DEF_TYPE_TYPE_MASK;

}



static u8 mtrr_disabled_type(void)

{

	/*

	 * Intel SDM 11.11.2.2: all MTRRs are disabled when

	 * IA32_MTRR_DEF_TYPE.E bit is cleared, and the UC

	 * memory type is applied to all of physical memory.

	 */

	return MTRR_TYPE_UNCACHABLE;

}



/*

* Three terms are used in the following code:

* - segment, it indicates the address segments covered by fixed MTRRs.
@@ -434,6 +444,8 @@ struct mtrr_iter { 


	/* output fields. */

	int mem_type;

	/* mtrr is completely disabled? */

	bool mtrr_disabled;

	/* [start, end) is not fully covered in MTRRs? */

	bool partial_map;
@@ -549,7 +561,7 @@ static void mtrr_lookup_var_next(struct mtrr_iter *iter) 
static void mtrr_lookup_start(struct mtrr_iter *iter)

{

	if (!mtrr_is_enabled(iter->mtrr_state)) {

		iter->partial_map = true;

		iter->mtrr_disabled = true;

		return;

	}
@@ -563,6 +575,7 @@ static void mtrr_lookup_init(struct mtrr_iter *iter, 
	iter->mtrr_state = mtrr_state;

	iter->start = start;

	iter->end = end;

	iter->mtrr_disabled = false;

	iter->partial_map = false;

	iter->fixed = false;

	iter->range = NULL;
@@ -656,6 +669,9 @@ u8 kvm_mtrr_get_guest_memory_type(struct kvm_vcpu *vcpu, gfn_t gfn) 
		return MTRR_TYPE_WRBACK;

	}



	if (iter.mtrr_disabled)

		return mtrr_disabled_type();



	/* It is not covered by MTRRs. */

	if (iter.partial_map) {

		/*
@@ -689,6 +705,9 @@ bool kvm_mtrr_check_gfn_range_consistency(struct kvm_vcpu *vcpu, gfn_t gfn, 
			return false;

	}



	if (iter.mtrr_disabled)

		return true;



	if (!iter.partial_map)

		return true;