diff options
| author | Vincent Donnefort <vdonnefort@google.com> | 2025-05-21 13:48:34 +0100 |
|---|---|---|
| committer | Marc Zyngier <maz@kernel.org> | 2025-05-21 14:33:51 +0100 |
| commit | c353fde17d8f7e710884532da50393cd22ddbfbe (patch) | |
| tree | 62d854146534e1251bed5011d0aa15d42263eb0a /arch/arm64/include | |
| parent | db14091d8f75852d960b18834c7bdb1b7c2bb74f (diff) | |
KVM: arm64: np-guest CMOs with PMD_SIZE fixmap
With the introduction of stage-2 huge mappings in the pKVM hypervisor,
guest pages CMO is needed for PMD_SIZE size. Fixmap only supports
PAGE_SIZE and iterating over the huge-page is time consuming (mostly due
to TLBI on hyp_fixmap_unmap) which is a problem for EL2 latency.
Introduce a shared PMD_SIZE fixmap (hyp_fixblock_map/hyp_fixblock_unmap)
to improve guest page CMOs when stage-2 huge mappings are installed.
On a Pixel6, the iterative solution resulted in a latency of ~700us,
while the PMD_SIZE fixmap reduces it to ~100us.
Because of the horrendous private range allocation that would be
necessary, this is disabled for 64KiB pages systems.
Suggested-by: Quentin Perret <qperret@google.com>
Signed-off-by: Vincent Donnefort <vdonnefort@google.com>
Signed-off-by: Quentin Perret <qperret@google.com>
Link: https://lore.kernel.org/r/20250521124834.1070650-11-vdonnefort@google.com
Signed-off-by: Marc Zyngier <maz@kernel.org>
Diffstat (limited to 'arch/arm64/include')
| -rw-r--r-- | arch/arm64/include/asm/kvm_pgtable.h | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/arch/arm64/include/asm/kvm_pgtable.h b/arch/arm64/include/asm/kvm_pgtable.h index 1b43bcd2a679..2888b5d03757 100644 --- a/arch/arm64/include/asm/kvm_pgtable.h +++ b/arch/arm64/include/asm/kvm_pgtable.h @@ -59,6 +59,11 @@ typedef u64 kvm_pte_t; #define KVM_PHYS_INVALID (-1ULL) +#define KVM_PTE_TYPE BIT(1) +#define KVM_PTE_TYPE_BLOCK 0 +#define KVM_PTE_TYPE_PAGE 1 +#define KVM_PTE_TYPE_TABLE 1 + #define KVM_PTE_LEAF_ATTR_LO GENMASK(11, 2) #define KVM_PTE_LEAF_ATTR_LO_S1_ATTRIDX GENMASK(4, 2) |