KVM: MMU: fix decoding cache type from MTRR (d69afbc6) · Commits · 戴 / test

There are some bugs in current get_mtrr_type(); 1: bit 1 of mtrr_state->enabled is corresponding bit 11 of IA32_MTRR_DEF_TYPE MSR which completely control MTRR's enablement that means other bits are ignored if it is cleared 2: the fixed MTRR ranges are controlled by bit 0 of mtrr_state->enabled (bit 10 of IA32_MTRR_DEF_TYPE) 3: if MTRR is disabled, UC is applied to all of physical memory rather than mtrr_state->def_type Signed-off-by:

Xiao Guangrong <guangrong.xiao@linux.intel.com> Reviewed-by:

Wanpeng Li <wanpeng.li@linux.intel.com> Signed-off-by:

Paolo Bonzini <pbonzini@redhat.com>

arch/x86/kvm/mmu.c

+6 −8

Original line number	Diff line number	Diff line
		@@ -2431,19 +2431,20 @@ EXPORT_SYMBOL_GPL(kvm_mmu_unprotect_page);
		static int get_mtrr_type(struct mtrr_state_type *mtrr_state,
		u64 start, u64 end)
		{
		int i;
		u64 base, mask;
		u8 prev_match, curr_match;
		int num_var_ranges = KVM_NR_VAR_MTRR;
		int i, num_var_ranges = KVM_NR_VAR_MTRR;

		if (!mtrr_state->enabled)
		return 0xFF;
		/* MTRR is completely disabled, use UC for all of physical memory. */
		if (!(mtrr_state->enabled & 0x2))
		return MTRR_TYPE_UNCACHABLE;

		/* Make end inclusive end, instead of exclusive */
		end--;

		/* Look in fixed ranges. Just return the type as per start */
		if (mtrr_state->have_fixed && (start < 0x100000)) {
		if (mtrr_state->have_fixed && (mtrr_state->enabled & 0x1) &&
		(start < 0x100000)) {
		int idx;

		if (start < 0x80000) {
		@@ -2466,9 +2467,6 @@ static int get_mtrr_type(struct mtrr_state_type *mtrr_state,
		* Look of multiple ranges matching this address and pick type
		* as per MTRR precedence
		*/
		if (!(mtrr_state->enabled & 2))
		return mtrr_state->def_type;

		prev_match = 0xFF;
		for (i = 0; i < num_var_ranges; ++i) {
		unsigned short start_state, end_state;

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