[PATCH] riscv: kvm: Skip preventive hfence.gvma for new G-stage mappings with Svvptc
"Dylan.Wu" <[email protected]>
| Newsgroups | org.infradead.lists.kvm-riscv,org.infradead.lists.linux-riscv,org.kernel.vger.kvm,org.kernel.vger.linux-kernel |
|---|---|
| Message-ID | <[email protected]> |
For Invalid->Valid G-stage leaf PTE updates, the flush in kvm_riscv_gstage_set_pte() is preventive. When Svvptc is available, new valid PTEs become visible to the page-table walker within a bounded time, so an immediate hfence.gvma is unnecessary. Skip gstage_tlb_flush() for that case. Permission-restricting updates continue to use the existing flush path. Assisted-by: YuanSheng: deepseek-v4-pro Co-developed-by: Quan Zhou <[email protected]> Signed-off-by: Quan Zhou <[email protected]> Signed-off-by: Dylan.Wu <[email protected]> --- arch/riscv/kvm/gstage.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/arch/riscv/kvm/gstage.c b/arch/riscv/kvm/gstage.c index c4c3b7956..7b805112d 100644 --- a/arch/riscv/kvm/gstage.c +++ b/arch/riscv/kvm/gstage.c @@ -10,6 +10,8 @@ #include <linux/module.h> #include <linux/pgtable.h> #include <asm/kvm_gstage.h> +#include <asm/cpufeature.h> +#include <asm/hwcap.h> #ifdef CONFIG_64BIT unsigned long kvm_riscv_gstage_max_pgd_levels __ro_after_init = 3; @@ -171,8 +173,11 @@ int kvm_riscv_gstage_set_pte(struct kvm_gstage *gstage, } if (pte_val(*ptep) != pte_val(map->pte)) { + bool was_invalid = !pte_val(*ptep); set_pte(ptep, map->pte); - if (gstage_pte_leaf(ptep)) + if (gstage_pte_leaf(ptep) && + !(was_invalid && + riscv_has_extension_unlikely(RISCV_ISA_EXT_SVVPTC))) gstage_tlb_flush(gstage, current_level, map->addr); } -- 2.34.1 -- kvm-riscv mailing list [email protected] http://lists.infradead.org/mailman/listinfo/kvm-riscv