On 2025/9/3 下午9:07, Richard Henderson wrote:
On 9/3/25 10:48, Bibo Mao wrote:With function helper_tlbwr(), specified LoongArch TLB entry will be updated. There are two PTE pages in one TLB entry called even/odd pages. Supposing even/odd page is normal/none state, when odd page is added, TLB entry is changed as normal/normal state and even page keeps unchanged. In this situation, it is not necessary to flush QEMU TLB since even page keep unchanged and odd page is newly changed. Here check whether PTE page is the same or not, TLB flush can be skipped if both are the same or newly added. Signed-off-by: Bibo Mao <[email protected]> --- target/loongarch/tcg/tlb_helper.c | 33 ++++++++++++++++++++++++++----- 1 file changed, 28 insertions(+), 5 deletions(-)diff --git a/target/loongarch/tcg/tlb_helper.c b/target/loongarch/tcg/tlb_helper.cindex fcd03ca320..331b485b1a 100644 --- a/target/loongarch/tcg/tlb_helper.c +++ b/target/loongarch/tcg/tlb_helper.c @@ -302,16 +302,39 @@ void helper_tlbrd(CPULoongArchState *env) void helper_tlbwr(CPULoongArchState *env) { int index = FIELD_EX64(env->CSR_TLBIDX, CSR_TLBIDX, INDEX); + LoongArchTLB *old, new;Perhaps "new = { }", then ...+ new.tlb_misc = 0; + new.tlb_entry0 = 0; + new.tlb_entry1 = 0;... this is unnecessary.
yes, this is simpler with { }. Will do.
+ fill_tlb_entry(env, &new); + /* Check whether ASID/VPPN is the same */ + if (old->tlb_misc == new.tlb_misc) { + /* Check whether both even/odd pages is the same or invalid */ + tlb_v0 = FIELD_EX64(old->tlb_entry0, TLBENTRY, V); + tlb_v1 = FIELD_EX64(old->tlb_entry1, TLBENTRY, V); + if ((!tlb_v0 || new.tlb_entry0 == old->tlb_entry0) && + (!tlb_v1 || new.tlb_entry1 == old->tlb_entry1)) { + skip_inv = true; + } + } + + /* flush tlb before updating the entry */ + if (!skip_inv) { + invalidate_tlb(env, index); + } + old->tlb_misc = new.tlb_misc; + old->tlb_entry0 = new.tlb_entry0; + old->tlb_entry1 = new.tlb_entry1;Perhaps better as "*old = new".
Will do in this way. Regards Bibo Mao
Anyway, Reviewed-by: Richard Henderson <[email protected]> r~
