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Wed, 04 Jun 2025 23:15:31 -0700 (PDT) From: Anup Patel To: Atish Patra Cc: Palmer Dabbelt , Paul Walmsley , Alexandre Ghiti , Andrew Jones , Anup Patel , kvm@vger.kernel.org, kvm-riscv@lists.infradead.org, linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org, Anup Patel Subject: [PATCH 07/13] RISC-V: KVM: Don't flush TLB in gstage_set_pte() when PTE is unchanged Date: Thu, 5 Jun 2025 11:44:52 +0530 Message-ID: <20250605061458.196003-8-apatel@ventanamicro.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20250605061458.196003-1-apatel@ventanamicro.com> References: <20250605061458.196003-1-apatel@ventanamicro.com> Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit The gstage_set_pte() should flush remote TLB only when a leaf PTE changes so that unnecessary remote TLB flushes can be avoided. Signed-off-by: Anup Patel --- arch/riscv/kvm/mmu.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/arch/riscv/kvm/mmu.c b/arch/riscv/kvm/mmu.c index 1087ea74567b..d4eb1999b794 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; } -- 2.43.0