[PATCH 4/8] KVM: x86/mmu: Dedup macros for computing various page table masks

Sean Christopherson
2022-06-13T22:58:49Z

Provide common helper macros to generate various masks, shifts, etc...
for 32-bit vs. 64-bit page tables. Only the inputs differ, the actual
calculations are identical.

No functional change intended.

Signed-off-by: Sean Christopherson <seanjc@google.com>
---
arch/x86/kvm/mmu.h | 4 ++--
arch/x86/kvm/mmu/mmu.c | 15 ++++++---------
arch/x86/kvm/mmu/mmu_internal.h | 14 ++++++++++++++
arch/x86/kvm/mmu/paging.h | 9 +++++----
arch/x86/kvm/mmu/spte.h | 7 +++----
5 files changed, 30 insertions(+), 19 deletions(-)

diff --git a/arch/x86/kvm/mmu.h b/arch/x86/kvm/mmu.h
index d1021e34ac15..6efe6bd7fb6e 100644
--- a/arch/x86/kvm/mmu.h
+++ b/arch/x86/kvm/mmu.h
@@ -7,9 +7,9 @@
#include "cpuid.h"

#define PT64_PT_BITS 9
-#define PT64_ENT_PER_PAGE (1 << PT64_PT_BITS)
+#define PT64_ENT_PER_PAGE __PT_ENT_PER_PAGE(PT64_PT_BITS)
#define PT32_PT_BITS 10
-#define PT32_ENT_PER_PAGE (1 << PT32_PT_BITS)
+#define PT32_ENT_PER_PAGE __PT_ENT_PER_PAGE(PT32_PT_BITS)

#define PT_WRITABLE_SHIFT 1
#define PT_USER_SHIFT 2
diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index f1961fe3fe67..afe3deaa0d95 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -113,23 +113,20 @@ module_param(dbg, bool, 0644);

#define PT32_LEVEL_BITS 10

-#define PT32_LEVEL_SHIFT(level) \
- (PAGE_SHIFT + (level - 1) * PT32_LEVEL_BITS)
+#define PT32_LEVEL_SHIFT(level) __PT_LEVEL_SHIFT(level, PT32_LEVEL_BITS)

#define PT32_LVL_OFFSET_MASK(level) \
- (PT32_BASE_ADDR_MASK & ((1ULL << (PAGE_SHIFT + (((level) - 1) \
- * PT32_LEVEL_BITS))) - 1))
-
-#define PT32_INDEX(address, level)\
- (((address) >> PT32_LEVEL_SHIFT(level)) & ((1 << PT32_LEVEL_BITS) - 1))
+ __PT_LVL_OFFSET_MASK(PT32_BASE_ADDR_MASK, level, PT32_LEVEL_BITS)

+#define PT32_INDEX(address, level) __PT_INDEX(address, level, PT32_LEVEL_BITS)

#define PT32_BASE_ADDR_MASK PAGE_MASK
+
#define PT32_DIR_BASE_ADDR_MASK \
(PAGE_MASK & ~((1ULL << (PAGE_SHIFT + PT32_LEVEL_BITS)) - 1))
+
#define PT32_LVL_ADDR_MASK(level) \
- (PAGE_MASK & ~((1ULL << (PAGE_SHIFT + (((level) - 1) \
- * PT32_LEVEL_BITS))) - 1))
+ __PT_LVL_ADDR_MASK(PT32_BASE_ADDR_MASK, level, PT32_LEVEL_BITS)

#include <trace/events/kvm.h>

diff --git a/arch/x86/kvm/mmu/mmu_internal.h b/arch/x86/kvm/mmu/mmu_internal.h
index bd2a26897b97..5e1e3c8f8aaa 100644
--- a/arch/x86/kvm/mmu/mmu_internal.h
+++ b/arch/x86/kvm/mmu/mmu_internal.h
@@ -20,6 +20,20 @@ extern bool dbg;
#define MMU_WARN_ON(x) do { } while (0)
#endif

+/* Page table builder macros common to shadow (host) PTEs and guest PTEs. */
+#define __PT_LEVEL_SHIFT(level, bits_per_level) \
+ (PAGE_SHIFT + ((level) - 1) * (bits_per_level))
+#define __PT_INDEX(address, level, bits_per_level) \
+ (((address) >> __PT_LEVEL_SHIFT(level, bits_per_level)) & ((1 << (bits_per_level)) - 1))
+
+#define __PT_LVL_ADDR_MASK(base_addr_mask, level, bits_per_level) \
+ ((base_addr_mask) & ~((1ULL << (PAGE_SHIFT + (((level) - 1) * (bits_per_level)))) - 1))
+
+#define __PT_LVL_OFFSET_MASK(base_addr_mask, level, bits_per_level) \
+ ((base_addr_mask) & ((1ULL << (PAGE_SHIFT + (((level) - 1) * (bits_per_level)))) - 1))
+
+#define __PT_ENT_PER_PAGE(bits_per_level) (1 << (bits_per_level))
+
/*
* Unlike regular MMU roots, PAE "roots", a.k.a. PDPTEs/PDPTRs, have a PRESENT
* bit, and thus are guaranteed to be non-zero when valid. And, when a guest
diff --git a/arch/x86/kvm/mmu/paging.h b/arch/x86/kvm/mmu/paging.h
index de8ab323bb70..23f3f64b8092 100644
--- a/arch/x86/kvm/mmu/paging.h
+++ b/arch/x86/kvm/mmu/paging.h
@@ -4,11 +4,12 @@
#define __KVM_X86_PAGING_H

#define GUEST_PT64_BASE_ADDR_MASK (((1ULL << 52) - 1) & ~(u64)(PAGE_SIZE-1))
+
#define PT64_LVL_ADDR_MASK(level) \
- (GUEST_PT64_BASE_ADDR_MASK & ~((1ULL << (PAGE_SHIFT + (((level) - 1) \
- * PT64_LEVEL_BITS))) - 1))
+ __PT_LVL_ADDR_MASK(GUEST_PT64_BASE_ADDR_MASK, level, PT64_LEVEL_BITS)
+
#define PT64_LVL_OFFSET_MASK(level) \
- (GUEST_PT64_BASE_ADDR_MASK & ((1ULL << (PAGE_SHIFT + (((level) - 1) \
- * PT64_LEVEL_BITS))) - 1))
+ __PT_LVL_OFFSET_MASK(GUEST_PT64_BASE_ADDR_MASK, level, PT64_LEVEL_BITS)
+
#endif /* __KVM_X86_PAGING_H */

diff --git a/arch/x86/kvm/mmu/spte.h b/arch/x86/kvm/mmu/spte.h
index 0127bb6e3c7d..d5a8183b7232 100644
--- a/arch/x86/kvm/mmu/spte.h
+++ b/arch/x86/kvm/mmu/spte.h
@@ -55,11 +55,10 @@ static_assert(SPTE_TDP_AD_ENABLED_MASK == 0);

#define PT64_LEVEL_BITS 9

-#define PT64_LEVEL_SHIFT(level) \
- (PAGE_SHIFT + (level - 1) * PT64_LEVEL_BITS)
+#define PT64_LEVEL_SHIFT(level) __PT_LEVEL_SHIFT(level, PT64_LEVEL_BITS)
+
+#define PT64_INDEX(address, level) __PT_INDEX(address, level, PT64_LEVEL_BITS)

-#define PT64_INDEX(address, level)\
- (((address) >> PT64_LEVEL_SHIFT(level)) & ((1 << PT64_LEVEL_BITS) - 1))
#define SHADOW_PT_INDEX(addr, level) PT64_INDEX(addr, level)

/*
--
2.36.1.476.g0c4daa206d-goog