bool can_unsync, bool host_writable, bool ad_disabled,
u64 *new_spte)
{
- u64 spte = 0;
+ u64 spte = SPTE_MMU_PRESENT_MASK;
int ret = 0;
if (ad_disabled)
u64 make_nonleaf_spte(u64 *child_pt, bool ad_disabled)
{
- u64 spte;
+ u64 spte = SPTE_MMU_PRESENT_MASK;
- spte = __pa(child_pt) | shadow_present_mask | PT_WRITABLE_MASK |
- shadow_user_mask | shadow_x_mask | shadow_me_mask;
+ spte |= __pa(child_pt) | shadow_present_mask | PT_WRITABLE_MASK |
+ shadow_user_mask | shadow_x_mask | shadow_me_mask;
if (ad_disabled)
spte |= SPTE_TDP_AD_DISABLED_MASK;
#include "mmu_internal.h"
/*
+ * A MMU present SPTE is backed by actual memory and may or may not be present
+ * in hardware. E.g. MMIO SPTEs are not considered present. Use bit 11, as it
+ * is ignored by all flavors of SPTEs and checking a low bit often generates
+ * better code than for a high bit, e.g. 56+. MMU present checks are pervasive
+ * enough that the improved code generation is noticeable in KVM's footprint.
+ */
+#define SPTE_MMU_PRESENT_MASK BIT_ULL(11)
+
+/*
* TDP SPTES (more specifically, EPT SPTEs) may not have A/D bits, and may also
* be restricted to using write-protection (for L2 when CPU dirty logging, i.e.
* PML, is enabled). Use bits 52 and 53 to hold the type of A/D tracking that
#undef SHADOW_ACC_TRACK_SAVED_MASK
/*
- * Due to limited space in PTEs, the MMIO generation is a 20 bit subset of
+ * Due to limited space in PTEs, the MMIO generation is a 19 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 9-19 of the MMIO generation are propagated to spte bits 52-62
+ * Bits 0-7 of the MMIO generation are propagated to spte bits 3-10
+ * Bits 8-18 of the MMIO generation are propagated to spte bits 52-62
*
* 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
*/
#define MMIO_SPTE_GEN_LOW_START 3
-#define MMIO_SPTE_GEN_LOW_END 11
+#define MMIO_SPTE_GEN_LOW_END 10
#define MMIO_SPTE_GEN_HIGH_START 52
#define MMIO_SPTE_GEN_HIGH_END 62
MMIO_SPTE_GEN_LOW_START)
#define MMIO_SPTE_GEN_HIGH_MASK GENMASK_ULL(MMIO_SPTE_GEN_HIGH_END, \
MMIO_SPTE_GEN_HIGH_START)
+static_assert(!(SPTE_MMU_PRESENT_MASK &
+ (MMIO_SPTE_GEN_LOW_MASK | MMIO_SPTE_GEN_HIGH_MASK)));
#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 == 11);
+static_assert(MMIO_SPTE_GEN_LOW_BITS == 8 && MMIO_SPTE_GEN_HIGH_BITS == 11);
#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)
static inline bool is_shadow_present_pte(u64 pte)
{
- return (pte != 0) && !is_mmio_spte(pte) && !is_removed_spte(pte);
+ return !!(pte & SPTE_MMU_PRESENT_MASK);
}
static inline bool is_large_pte(u64 pte)