diff options
| author | Anup Patel <apatel@ventanamicro.com> | 2025-06-18 17:05:25 +0530 |
|---|---|---|
| committer | Anup Patel <anup@brainfault.org> | 2025-07-28 22:27:16 +0530 |
| commit | eaa98ba20be088eeb252061f216c299442ba5a69 (patch) | |
| tree | 8ef12f5820e59d840ef3ba400483b4bb1009b594 | |
| parent | 7584eb611e8ef22aca3b801f7fd8529892b70901 (diff) | |
RISC-V: KVM: Don't flush TLB when PTE is unchanged
The gstage_set_pte() and gstage_op_pte() should flush TLB only when
a leaf PTE changes so that unnecessary TLB flushes can be avoided.
Signed-off-by: Anup Patel <apatel@ventanamicro.com>
Reviewed-by: Atish Patra <atishp@rivosinc.com>
Tested-by: Atish Patra <atishp@rivosinc.com>
Reviewed-by: Nutty Liu <liujingqi@lanxincomputing.com>
Link: https://lore.kernel.org/r/20250618113532.471448-6-apatel@ventanamicro.com
Signed-off-by: Anup Patel <anup@brainfault.org>
| -rw-r--r-- | arch/riscv/kvm/mmu.c | 14 |
1 files changed, 9 insertions, 5 deletions
diff --git a/arch/riscv/kvm/mmu.c b/arch/riscv/kvm/mmu.c index 1087ea74567b..29f1bd853a66 100644 --- a/arch/riscv/kvm/mmu.c +++ b/arch/riscv/kvm/mmu.c @@ -167,9 +167,11 @@ static int gstage_set_pte(struct kvm *kvm, u32 level, ptep = &next_ptep[gstage_pte_index(addr, current_level)]; } - set_pte(ptep, *new_pte); - if (gstage_pte_leaf(ptep)) - gstage_remote_tlb_flush(kvm, current_level, addr); + if (pte_val(*ptep) != pte_val(*new_pte)) { + set_pte(ptep, *new_pte); + if (gstage_pte_leaf(ptep)) + gstage_remote_tlb_flush(kvm, current_level, addr); + } return 0; } @@ -229,7 +231,7 @@ static void gstage_op_pte(struct kvm *kvm, gpa_t addr, pte_t *ptep, u32 ptep_level, enum gstage_op op) { int i, ret; - pte_t *next_ptep; + pte_t old_pte, *next_ptep; u32 next_ptep_level; unsigned long next_page_size, page_size; @@ -258,11 +260,13 @@ static void gstage_op_pte(struct kvm *kvm, gpa_t addr, if (op == GSTAGE_OP_CLEAR) put_page(virt_to_page(next_ptep)); } else { + old_pte = *ptep; if (op == GSTAGE_OP_CLEAR) set_pte(ptep, __pte(0)); else if (op == GSTAGE_OP_WP) set_pte(ptep, __pte(pte_val(ptep_get(ptep)) & ~_PAGE_WRITE)); - gstage_remote_tlb_flush(kvm, ptep_level, addr); + if (pte_val(*ptep) != pte_val(old_pte)) + gstage_remote_tlb_flush(kvm, ptep_level, addr); } } |