[PATCH 20/45] KVM: Add local get_mtrr_type() to support MTRR

Avi Kivity
2008-12-08T11:39:52Z

From: Sheng Yang <sheng@linux.intel.com>

For EPT memory type support.

Signed-off-by: Sheng Yang <sheng@linux.intel.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
---
arch/x86/kvm/mmu.c | 104 ++++++++++++++++++++++++++++++++++++++++++++++++++++
1 files changed, 104 insertions(+), 0 deletions(-)

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 410ddbc..ac2304f 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -1393,6 +1393,110 @@ struct page *gva_to_page(struct kvm_vcpu *vcpu, gva_t gva)
return page;
}

+/*
+ * The function is based on mtrr_type_lookup() in
+ * arch/x86/kernel/cpu/mtrr/generic.c
+ */
+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;
+
+ if (!mtrr_state->enabled)
+ return 0xFF;
+
+ /* 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)) {
+ 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
+ */
+ 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;
+
+ if (!(mtrr_state->var_ranges[i].mask_lo & (1 << 11)))
+ continue;
+
+ base = (((u64)mtrr_state->var_ranges[i].base_hi) << 32) +
+ (mtrr_state->var_ranges[i].base_lo & PAGE_MASK);
+ mask = (((u64)mtrr_state->var_ranges[i].mask_hi) << 32) +
+ (mtrr_state->var_ranges[i].mask_lo & PAGE_MASK);
+
+ start_state = ((start & mask) == (base & mask));
+ end_state = ((end & mask) == (base & mask));
+ if (start_state != end_state)
+ return 0xFE;
+
+ if ((start & mask) != (base & mask))
+ continue;
+
+ curr_match = mtrr_state->var_ranges[i].base_lo & 0xff;
+ if (prev_match == 0xFF) {
+ prev_match = curr_match;
+ continue;
+ }
+
+ if (prev_match == MTRR_TYPE_UNCACHABLE ||
+ curr_match == MTRR_TYPE_UNCACHABLE)
+ return MTRR_TYPE_UNCACHABLE;
+
+ if ((prev_match == MTRR_TYPE_WRBACK &&
+ curr_match == MTRR_TYPE_WRTHROUGH) ||
+ (prev_match == MTRR_TYPE_WRTHROUGH &&
+ curr_match == MTRR_TYPE_WRBACK)) {
+ prev_match = MTRR_TYPE_WRTHROUGH;
+ curr_match = MTRR_TYPE_WRTHROUGH;
+ }
+
+ if (prev_match != curr_match)
+ return MTRR_TYPE_UNCACHABLE;
+ }
+
+ if (prev_match != 0xFF)
+ return prev_match;
+
+ return mtrr_state->def_type;
+}
+
+static u8 get_memory_type(struct kvm_vcpu *vcpu, gfn_t gfn)
+{
+ u8 mtrr;
+
+ mtrr = get_mtrr_type(&vcpu->arch.mtrr_state, gfn << PAGE_SHIFT,
+ (gfn << PAGE_SHIFT) + PAGE_SIZE);
+ if (mtrr == 0xfe || mtrr == 0xff)
+ mtrr = MTRR_TYPE_WRBACK;
+ return mtrr;
+}
+
static int kvm_unsync_page(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp)
{
unsigned index;
--
1.6.0.3