[PATCH v7 36/42] target/arm: Complete TBI clearing for user-only for SVE

From: Richard Henderson <richard.henderson@linaro.org>
To: qemu-devel@nongnu.org
Cc: peter.maydell@linaro.org, qemu-arm@nongnu.org, steplong@quicinc.com
Subject: [PATCH v7 36/42] target/arm: Complete TBI clearing for user-only for SVE
Date: Tue,  2 Jun 2020 18:13:11 -0700	[thread overview]
Message-ID: <20200603011317.473934-37-richard.henderson@linaro.org> (raw)
In-Reply-To: <20200603011317.473934-1-richard.henderson@linaro.org>

There are a number of paths by which the TBI is still intact
for user-only in the SVE helpers.

Because we currently always set TBI for user-only, we do not
need to pass down the actual TBI setting from above, and we
can remove the top byte in the inner-most primitives, so that
none are forgotten.  Moreover, this keeps the "dirty" pointer
around at the higher levels, where we need it for any MTE checking.

Since the normal case, especially for user-only, goes through
RAM, this clearing merely adds two insns per page lookup, which
will be completely in the noise.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 target/arm/sve_helper.c | 19 +++++++++++++++++--
 1 file changed, 17 insertions(+), 2 deletions(-)

diff --git a/target/arm/sve_helper.c b/target/arm/sve_helper.c
index 2d2aa14b43..460a3e5937 100644
--- a/target/arm/sve_helper.c
+++ b/target/arm/sve_helper.c
@@ -3966,14 +3966,16 @@ static void sve_##NAME##_host(void *vd, intptr_t reg_off, void *host)  \
 static void sve_##NAME##_tlb(CPUARMState *env, void *vd, intptr_t reg_off,  \
                              target_ulong addr, uintptr_t ra)               \
 {                                                                           \
-    *(TYPEE *)(vd + H(reg_off)) = (TYPEM)TLB(env, addr, ra);                \
+    *(TYPEE *)(vd + H(reg_off)) =                                           \
+        (TYPEM)TLB(env, useronly_clean_ptr(addr), ra);	                    \
 }
 
 #define DO_ST_TLB(NAME, H, TYPEE, TYPEM, TLB) \
 static void sve_##NAME##_tlb(CPUARMState *env, void *vd, intptr_t reg_off,  \
                              target_ulong addr, uintptr_t ra)               \
 {                                                                           \
-    TLB(env, addr, (TYPEM)*(TYPEE *)(vd + H(reg_off)), ra);                 \
+    TLB(env, useronly_clean_ptr(addr),                                      \
+        (TYPEM)*(TYPEE *)(vd + H(reg_off)), ra);                            \
 }
 
 #define DO_LD_PRIM_1(NAME, H, TE, TM)                   \
@@ -4091,6 +4093,19 @@ static bool sve_probe_page(SVEHostPage *info, bool nofault,
     int flags;
 
     addr += mem_off;
+
+    /*
+     * User-only currently always issues with TBI.  See the comment
+     * above useronly_clean_ptr.  Usually we clean this top byte away
+     * during translation, but we can't do that for e.g. vector + imm
+     * addressing modes.
+     *
+     * We currently always enable TBI for user-only, and do not provide
+     * a way to turn it off.  So clean the pointer unconditionally here,
+     * rather than look it up here, or pass it down from above.
+     */
+    addr = useronly_clean_ptr(addr);
+
     flags = probe_access_flags(env, addr, access_type, mmu_idx, nofault,
                                &info->host, retaddr);
     info->flags = flags;
-- 
2.25.1


