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Diffstat (limited to 'arch/x86/kvm/mmu/mmu.c')
-rw-r--r--arch/x86/kvm/mmu/mmu.c46
1 files changed, 19 insertions, 27 deletions
diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index 87e9ba27ada1..ea6fa05e2fd9 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -343,6 +343,8 @@ void kvm_mmu_set_mmio_spte_mask(u64 mmio_mask, u64 mmio_value, u64 access_mask)
{
BUG_ON((u64)(unsigned)access_mask != access_mask);
BUG_ON((mmio_mask & mmio_value) != mmio_value);
+ WARN_ON(mmio_value & (shadow_nonpresent_or_rsvd_mask << shadow_nonpresent_or_rsvd_mask_len));
+ WARN_ON(mmio_value & shadow_nonpresent_or_rsvd_lower_gfn_mask);
shadow_mmio_value = mmio_value | SPTE_MMIO_MASK;
shadow_mmio_mask = mmio_mask | SPTE_SPECIAL_MASK;
shadow_mmio_access_mask = access_mask;
@@ -591,16 +593,15 @@ static void kvm_mmu_reset_all_pte_masks(void)
* the most significant bits of legal physical address space.
*/
shadow_nonpresent_or_rsvd_mask = 0;
- low_phys_bits = boot_cpu_data.x86_cache_bits;
- if (boot_cpu_data.x86_cache_bits <
- 52 - shadow_nonpresent_or_rsvd_mask_len) {
+ low_phys_bits = boot_cpu_data.x86_phys_bits;
+ if (boot_cpu_has_bug(X86_BUG_L1TF) &&
+ !WARN_ON_ONCE(boot_cpu_data.x86_cache_bits >=
+ 52 - shadow_nonpresent_or_rsvd_mask_len)) {
+ low_phys_bits = boot_cpu_data.x86_cache_bits
+ - shadow_nonpresent_or_rsvd_mask_len;
shadow_nonpresent_or_rsvd_mask =
- rsvd_bits(boot_cpu_data.x86_cache_bits -
- shadow_nonpresent_or_rsvd_mask_len,
- boot_cpu_data.x86_cache_bits - 1);
- low_phys_bits -= shadow_nonpresent_or_rsvd_mask_len;
- } else
- WARN_ON_ONCE(boot_cpu_has_bug(X86_BUG_L1TF));
+ rsvd_bits(low_phys_bits, boot_cpu_data.x86_cache_bits - 1);
+ }
shadow_nonpresent_or_rsvd_lower_gfn_mask =
GENMASK_ULL(low_phys_bits - 1, PAGE_SHIFT);
@@ -6131,25 +6132,16 @@ static void kvm_set_mmio_spte_mask(void)
u64 mask;
/*
- * Set the reserved bits and the present bit of an paging-structure
- * entry to generate page fault with PFER.RSV = 1.
- */
-
- /*
- * Mask the uppermost physical address bit, which would be reserved as
- * long as the supported physical address width is less than 52.
+ * Set a reserved PA bit in MMIO SPTEs to generate page faults with
+ * PFEC.RSVD=1 on MMIO accesses. 64-bit PTEs (PAE, x86-64, and EPT
+ * paging) support a maximum of 52 bits of PA, i.e. if the CPU supports
+ * 52-bit physical addresses then there are no reserved PA bits in the
+ * PTEs and so the reserved PA approach must be disabled.
*/
- mask = 1ull << 51;
-
- /* Set the present bit. */
- mask |= 1ull;
-
- /*
- * If reserved bit is not supported, clear the present bit to disable
- * mmio page fault.
- */
- if (shadow_phys_bits == 52)
- mask &= ~1ull;
+ if (shadow_phys_bits < 52)
+ mask = BIT_ULL(51) | PT_PRESENT_MASK;
+ else
+ mask = 0;
kvm_mmu_set_mmio_spte_mask(mask, mask, ACC_WRITE_MASK | ACC_USER_MASK);
}