[PULL 06/84] accel/tcg: Honor TLB_DISCARD_WRITE in atomic_mmu_lookup

Richard Henderson posted 84 patches 2 years, 1 month ago
Maintainers: Richard Henderson <richard.henderson@linaro.org>, Paolo Bonzini <pbonzini@redhat.com>, Eduardo Habkost <eduardo@habkost.net>, Marcel Apfelbaum <marcel.apfelbaum@gmail.com>, "Philippe Mathieu-Daudé" <philmd@linaro.org>, Yanan Wang <wangyanan55@huawei.com>, "Marc-André Lureau" <marcandre.lureau@redhat.com>, "Daniel P. Berrangé" <berrange@redhat.com>, Thomas Huth <thuth@redhat.com>, Stefan Hajnoczi <stefanha@redhat.com>, Peter Maydell <peter.maydell@linaro.org>, Michael Rolnik <mrolnik@gmail.com>, "Edgar E. Iglesias" <edgar.iglesias@gmail.com>, Taylor Simpson <tsimpson@quicinc.com>, Alessandro Di Federico <ale@rev.ng>, Anton Johansson <anjo@rev.ng>, Song Gao <gaosong@loongson.cn>, Xiaojuan Yang <yangxiaojuan@loongson.cn>, Laurent Vivier <laurent@vivier.eu>, Aurelien Jarno <aurelien@aurel32.net>, Jiaxun Yang <jiaxun.yang@flygoat.com>, Aleksandar Rikalo <aleksandar.rikalo@syrmia.com>, Chris Wulff <crwulff@gmail.com>, Marek Vasut <marex@denx.de>, Stafford Horne <shorne@gmail.com>, Daniel Henrique Barboza <danielhb413@gmail.com>, "Cédric Le Goater" <clg@kaod.org>, David Gibson <david@gibson.dropbear.id.au>, Greg Kurz <groug@kaod.org>, Palmer Dabbelt <palmer@dabbelt.com>, Alistair Francis <alistair.francis@wdc.com>, Bin Meng <bin.meng@windriver.com>, Weiwei Li <liweiwei@iscas.ac.cn>, Liu Zhiwei <zhiwei_liu@linux.alibaba.com>, Christoph Muellner <christoph.muellner@vrull.eu>, Yoshinori Sato <ysato@users.sourceforge.jp>, David Hildenbrand <david@redhat.com>, Ilya Leoshkevich <iii@linux.ibm.com>, Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>, Artyom Tarasenko <atar4qemu@gmail.com>, Bastian Koppelmann <kbastian@mail.uni-paderborn.de>, Max Filippov <jcmvbkbc@gmail.com>
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[PULL 06/84] accel/tcg: Honor TLB_DISCARD_WRITE in atomic_mmu_lookup
Posted by Richard Henderson 2 years, 1 month ago
Using an atomic write or read-write insn on ROM is basically
a happens-never case.  Handle it via stop-the-world, which
will generate non-atomic serial code, where we can correctly
ignore the write while producing the correct read result.

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 accel/tcg/cputlb.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/accel/tcg/cputlb.c b/accel/tcg/cputlb.c
index deafcc7f15..b49fb0d754 100644
--- a/accel/tcg/cputlb.c
+++ b/accel/tcg/cputlb.c
@@ -1831,7 +1831,7 @@ static void *atomic_mmu_lookup(CPUArchState *env, target_ulong addr,
     }
 
     /* Notice an IO access or a needs-MMU-lookup access */
-    if (unlikely(tlb_addr & TLB_MMIO)) {
+    if (unlikely(tlb_addr & (TLB_MMIO | TLB_DISCARD_WRITE))) {
         /* There's really nothing that can be done to
            support this apart from stop-the-world.  */
         goto stop_the_world;
-- 
2.34.1