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Diffstat (limited to 'arch/x86/kvm/mmu/spte.h')
-rw-r--r--arch/x86/kvm/mmu/spte.h25
1 files changed, 18 insertions, 7 deletions
diff --git a/arch/x86/kvm/mmu/spte.h b/arch/x86/kvm/mmu/spte.h
index 5c75a451c000..2b3a30bd38b0 100644
--- a/arch/x86/kvm/mmu/spte.h
+++ b/arch/x86/kvm/mmu/spte.h
@@ -56,11 +56,11 @@
#define SPTE_MMU_WRITEABLE (1ULL << (PT_FIRST_AVAIL_BITS_SHIFT + 1))
/*
- * Due to limited space in PTEs, the MMIO generation is a 19 bit subset of
+ * Due to limited space in PTEs, the MMIO generation is a 18 bit subset of
* the memslots generation and is derived as follows:
*
* Bits 0-8 of the MMIO generation are propagated to spte bits 3-11
- * Bits 9-18 of the MMIO generation are propagated to spte bits 52-61
+ * Bits 9-17 of the MMIO generation are propagated to spte bits 54-62
*
* The KVM_MEMSLOT_GEN_UPDATE_IN_PROGRESS flag is intentionally not included in
* the MMIO generation number, as doing so would require stealing a bit from
@@ -69,18 +69,29 @@
* requires a full MMU zap). The flag is instead explicitly queried when
* checking for MMIO spte cache hits.
*/
-#define MMIO_SPTE_GEN_MASK GENMASK_ULL(17, 0)
#define MMIO_SPTE_GEN_LOW_START 3
#define MMIO_SPTE_GEN_LOW_END 11
-#define MMIO_SPTE_GEN_LOW_MASK GENMASK_ULL(MMIO_SPTE_GEN_LOW_END, \
- MMIO_SPTE_GEN_LOW_START)
#define MMIO_SPTE_GEN_HIGH_START PT64_SECOND_AVAIL_BITS_SHIFT
#define MMIO_SPTE_GEN_HIGH_END 62
+
+#define MMIO_SPTE_GEN_LOW_MASK GENMASK_ULL(MMIO_SPTE_GEN_LOW_END, \
+ MMIO_SPTE_GEN_LOW_START)
#define MMIO_SPTE_GEN_HIGH_MASK GENMASK_ULL(MMIO_SPTE_GEN_HIGH_END, \
MMIO_SPTE_GEN_HIGH_START)
+#define MMIO_SPTE_GEN_LOW_BITS (MMIO_SPTE_GEN_LOW_END - MMIO_SPTE_GEN_LOW_START + 1)
+#define MMIO_SPTE_GEN_HIGH_BITS (MMIO_SPTE_GEN_HIGH_END - MMIO_SPTE_GEN_HIGH_START + 1)
+
+/* remember to adjust the comment above as well if you change these */
+static_assert(MMIO_SPTE_GEN_LOW_BITS == 9 && MMIO_SPTE_GEN_HIGH_BITS == 9);
+
+#define MMIO_SPTE_GEN_LOW_SHIFT (MMIO_SPTE_GEN_LOW_START - 0)
+#define MMIO_SPTE_GEN_HIGH_SHIFT (MMIO_SPTE_GEN_HIGH_START - MMIO_SPTE_GEN_LOW_BITS)
+
+#define MMIO_SPTE_GEN_MASK GENMASK_ULL(MMIO_SPTE_GEN_LOW_BITS + MMIO_SPTE_GEN_HIGH_BITS - 1, 0)
+
extern u64 __read_mostly shadow_nx_mask;
extern u64 __read_mostly shadow_x_mask; /* mutual exclusive with nx_mask */
extern u64 __read_mostly shadow_user_mask;
@@ -228,8 +239,8 @@ static inline u64 get_mmio_spte_generation(u64 spte)
{
u64 gen;
- gen = (spte & MMIO_SPTE_GEN_LOW_MASK) >> MMIO_SPTE_GEN_LOW_START;
- gen |= (spte & MMIO_SPTE_GEN_HIGH_MASK) >> MMIO_SPTE_GEN_HIGH_START;
+ gen = (spte & MMIO_SPTE_GEN_LOW_MASK) >> MMIO_SPTE_GEN_LOW_SHIFT;
+ gen |= (spte & MMIO_SPTE_GEN_HIGH_MASK) >> MMIO_SPTE_GEN_HIGH_SHIFT;
return gen;
}