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From: David Hildenbrand <david@redhat.com>
To: qemu-devel@nongnu.org
Cc: Florian Weimer <fweimer@redhat.com>,
	Thomas Huth <thuth@redhat.com>,
	David Hildenbrand <david@redhat.com>,
	Cornelia Huck <cohuck@redhat.com>,
	Stefano Brivio <sbrivio@redhat.com>,
	qemu-s390x@nongnu.org, Richard Henderson <rth@twiddle.net>
Subject: [Qemu-devel] [PATCH v2 15/28] s390x/tcg: Fault-safe memset
Date: Fri,  6 Sep 2019 09:57:37 +0200
Message-ID: <20190906075750.14791-16-david@redhat.com> (raw)
In-Reply-To: <20190906075750.14791-1-david@redhat.com>

Replace fast_memset() by access_memset(), that first tries to probe
access to all affected pages (maximum is two). We'll use the same
mechanism for other types of accesses soon.

Only in very rare cases (especially TLB_NOTDIRTY), we'll have to
fallback to ld/st helpers.

Signed-off-by: David Hildenbrand <david@redhat.com>
---
 target/s390x/mem_helper.c | 99 ++++++++++++++++++++++++++++++---------
 1 file changed, 77 insertions(+), 22 deletions(-)

diff --git a/target/s390x/mem_helper.c b/target/s390x/mem_helper.c
index 8dd58b3ab1..8d654b24e7 100644
--- a/target/s390x/mem_helper.c
+++ b/target/s390x/mem_helper.c
@@ -117,27 +117,82 @@ static inline void cpu_stsize_data_ra(CPUS390XState *env, uint64_t addr,
     }
 }
 
-static void fast_memset(CPUS390XState *env, uint64_t dest, uint8_t byte,
-                        uint32_t l, uintptr_t ra)
-{
-    int mmu_idx = cpu_mmu_index(env, false);
+/*
+ * An access covers at most 4096 bytes and therefore at most two pages. If
+ * we can't access the host page directly, we'll have to do I/O access
+ * via ld/st helpers.
+ */
+typedef struct S390Access {
+    target_ulong vaddr1;
+    target_ulong vaddr2;
+    char *haddr1;
+    char *haddr2;
+    uint16_t size1;
+    uint16_t size2;
+} S390Access;
+
+static S390Access access_prepare_idx(CPUS390XState *env, vaddr vaddr, int size,
+                                     MMUAccessType access_type, int mmu_idx,
+                                     uintptr_t ra)
+{
+    S390Access access = {
+        .vaddr1 = vaddr,
+        .size1 = MIN(size, -(vaddr | TARGET_PAGE_MASK)),
+    };
+
+    g_assert(size > 0 && size <= 4096);
+    access.haddr1 = probe_access(env, access.vaddr1, access.size1, access_type,
+                                 mmu_idx, ra);
+
+    if (unlikely(access.size1 != size)) {
+        /* The access crosses page boundaries. */
+        access.vaddr2 = wrap_address(env, vaddr + access.size1);
+        access.size2 = size - access.size1;
+        access.haddr2 = probe_access(env, access.vaddr2, access.size2,
+                                     access_type, mmu_idx, ra);
+    }
+    return access;
+}
+
+static void access_memset_idx(CPUS390XState *env, vaddr vaddr, uint8_t byte,
+                              int size, int mmu_idx, uintptr_t ra)
+{
+    S390Access desta = access_prepare_idx(env, vaddr, size, MMU_DATA_STORE,
+                                          mmu_idx, ra);
+#ifdef CONFIG_USER_ONLY
+    g_assert(desta.haddr1 && (desta.haddr2 || !desta.size2));
+    memset(desta.haddr1, byte, desta.size1);
+    memset(desta.haddr2, byte, desta.size2);
+#else
+    TCGMemOpIdx oi = make_memop_idx(MO_UB, mmu_idx);
+    int i;
 
-    while (l > 0) {
-        void *p = tlb_vaddr_to_host(env, dest, MMU_DATA_STORE, mmu_idx);
-        if (p) {
-            /* Access to the whole page in write mode granted.  */
-            uint32_t l_adj = adj_len_to_page(l, dest);
-            memset(p, byte, l_adj);
-            dest += l_adj;
-            l -= l_adj;
-        } else {
-            /* We failed to get access to the whole page. The next write
-               access will likely fill the QEMU TLB for the next iteration.  */
-            cpu_stb_data_ra(env, dest, byte, ra);
-            dest++;
-            l--;
+    if (likely(desta.haddr1)) {
+        memset(desta.haddr1, byte, desta.size1);
+    } else {
+        for (i = 0; i < desta.size1; i++) {
+            helper_ret_stb_mmu(env, desta.vaddr1 + i, byte, oi, ra);
+        }
+    }
+    if (likely(!desta.size2)) {
+        return;
+    }
+    if (likely(desta.haddr2)) {
+            memset(desta.haddr2, byte, desta.size2);
+    } else {
+        for (i = 0; i < desta.size2; i++) {
+            helper_ret_stb_mmu(env, desta.vaddr2 + i, byte, oi, ra);
         }
     }
+#endif
+}
+
+static void access_memset(CPUS390XState *env, vaddr vaddr, uint8_t byte,
+                          int size, uintptr_t ra)
+{
+    int mmu_idx = cpu_mmu_index(env, false);
+
+    access_memset_idx(env, vaddr, byte, size, mmu_idx, ra);
 }
 
 #ifndef CONFIG_USER_ONLY
@@ -267,7 +322,7 @@ static uint32_t do_helper_xc(CPUS390XState *env, uint32_t l, uint64_t dest,
 
     /* xor with itself is the same as memset(0) */
     if (src == dest) {
-        fast_memset(env, dest, 0, l + 1, ra);
+        access_memset(env, dest, 0, l + 1, ra);
         return 0;
     }
 
@@ -329,7 +384,7 @@ static uint32_t do_helper_mvc(CPUS390XState *env, uint32_t l, uint64_t dest,
      * behave like memmove().
      */
     if (dest == src + 1) {
-        fast_memset(env, dest, cpu_ldub_data_ra(env, src, ra), l, ra);
+        access_memset(env, dest, cpu_ldub_data_ra(env, src, ra), l, ra);
     } else if (!is_destructive_overlap(env, dest, src, l)) {
         fast_memmove(env, dest, src, l, ra);
     } else {
@@ -798,7 +853,7 @@ static inline uint32_t do_mvcl(CPUS390XState *env,
     } else if (wordsize == 1) {
         /* Pad the remaining area */
         *destlen -= len;
-        fast_memset(env, *dest, pad, len, ra);
+        access_memset(env, *dest, pad, len, ra);
         *dest = wrap_address(env, *dest + len);
     } else {
         /* The remaining length selects the padding byte. */
@@ -852,7 +907,7 @@ uint32_t HELPER(mvcl)(CPUS390XState *env, uint32_t r1, uint32_t r2)
     while (destlen) {
         cur_len = MIN(destlen, 2048);
         if (!srclen) {
-            fast_memset(env, dest, pad, cur_len, ra);
+            access_memset(env, dest, pad, cur_len, ra);
         } else {
             cur_len = MIN(cur_len, srclen);
 
-- 
2.21.0



  parent reply index

Thread overview: 68+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-09-06  7:57 [Qemu-devel] [PATCH v2 00/28] s390x/tcg: mem_helper: Fault-safe handling David Hildenbrand
2019-09-06  7:57 ` [Qemu-devel] [PATCH v2 01/28] s390x/tcg: Reset exception_index to -1 instead of 0 David Hildenbrand
2019-09-11 14:38   ` Richard Henderson
2019-09-06  7:57 ` [Qemu-devel] [PATCH v2 02/28] s390x/tcg: MVCL: Zero out unused bits of address David Hildenbrand
2019-09-11 14:40   ` Richard Henderson
2019-09-11 16:10     ` David Hildenbrand
2019-09-06  7:57 ` [Qemu-devel] [PATCH v2 03/28] s390x/tcg: MVCL: Detect destructive overlaps David Hildenbrand
2019-09-11 14:42   ` Richard Henderson
2019-09-06  7:57 ` [Qemu-devel] [PATCH v2 04/28] s390x/tcg: MVCL: Process max 2k bytes at a time David Hildenbrand
2019-09-11 14:52   ` Richard Henderson
2019-09-11 15:07     ` Richard Henderson
2019-09-11 16:12       ` David Hildenbrand
2019-09-06  7:57 ` [Qemu-devel] [PATCH v2 05/28] s390x/tcg: MVC: Increment the length once David Hildenbrand
2019-09-06  7:57 ` [Qemu-devel] [PATCH v2 06/28] s390x/tcg: MVC: Use is_destructive_overlap() David Hildenbrand
2019-09-11 14:54   ` Richard Henderson
2019-09-11 16:13     ` David Hildenbrand
2019-09-06  7:57 ` [Qemu-devel] [PATCH v2 07/28] s390x/tcg: MVPG: Check for specification exceptions David Hildenbrand
2019-09-11 14:57   ` Richard Henderson
2019-09-06  7:57 ` [Qemu-devel] [PATCH v2 08/28] s390x/tcg: MVPG: Properly wrap the addresses David Hildenbrand
2019-09-11 14:58   ` Richard Henderson
2019-09-06  7:57 ` [Qemu-devel] [PATCH v2 09/28] s390x/tcg: MVCLU/MVCLE: Process max 4k bytes at a time David Hildenbrand
2019-09-11 15:05   ` Richard Henderson
2019-09-11 16:14     ` David Hildenbrand
2019-09-06  7:57 ` [Qemu-devel] [PATCH v2 10/28] s390x/tcg: MVCS/MVCP: Check for special operation exceptions David Hildenbrand
2019-09-11 15:08   ` Richard Henderson
2019-09-06  7:57 ` [Qemu-devel] [PATCH v2 11/28] s390x/tcg: MVCS/MVCP: Properly wrap the length David Hildenbrand
2019-09-11 15:11   ` Richard Henderson
2019-09-11 16:15     ` David Hildenbrand
2019-09-06  7:57 ` [Qemu-devel] [PATCH v2 12/28] s390x/tcg: MVST: Check for specification exceptions David Hildenbrand
2019-09-11 15:14   ` Richard Henderson
2019-09-06  7:57 ` [Qemu-devel] [PATCH v2 13/28] s390x/tcg: MVST: Fix storing back the addresses to registers David Hildenbrand
2019-09-11 15:18   ` Richard Henderson
2019-09-11 16:15     ` David Hildenbrand
2019-09-06  7:57 ` [Qemu-devel] [PATCH v2 14/28] s390x/tcg: Always use MMU_USER_IDX for CONFIG_USER_ONLY David Hildenbrand
2019-09-11 15:19   ` Richard Henderson
2019-09-06  7:57 ` David Hildenbrand [this message]
2019-09-11 15:29   ` [Qemu-devel] [PATCH v2 15/28] s390x/tcg: Fault-safe memset Richard Henderson
2019-09-11 16:18     ` David Hildenbrand
2019-09-06  7:57 ` [Qemu-devel] [PATCH v2 16/28] s390x/tcg: Fault-safe memmove David Hildenbrand
2019-09-11 21:11   ` Richard Henderson
2019-09-11 22:03   ` Richard Henderson
2019-09-13 12:37     ` David Hildenbrand
2019-09-06  7:57 ` [Qemu-devel] [PATCH v2 17/28] s390x/tcg: MVCS/MVCP: Use access_memmove_idx() David Hildenbrand
2019-09-11 21:13   ` Richard Henderson
2019-09-06  7:57 ` [Qemu-devel] [PATCH v2 18/28] s390x/tcg: MVC: Fault-safe handling on destructive overlaps David Hildenbrand
2019-09-11 21:20   ` Richard Henderson
2019-09-06  7:57 ` [Qemu-devel] [PATCH v2 19/28] s390x/tcg: MVCLU: Fault-safe handling David Hildenbrand
2019-09-11 21:24   ` Richard Henderson
2019-09-06  7:57 ` [Qemu-devel] [PATCH v2 20/28] s390x/tcg: OC: " David Hildenbrand
2019-09-11 21:26   ` Richard Henderson
2019-09-16 12:01     ` David Hildenbrand
2019-09-06  7:57 ` [Qemu-devel] [PATCH v2 21/28] s390x/tcg: XC: " David Hildenbrand
2019-09-11 21:29   ` Richard Henderson
2019-09-06  7:57 ` [Qemu-devel] [PATCH v2 22/28] s390x/tcg: NC: " David Hildenbrand
2019-09-11 21:32   ` Richard Henderson
2019-09-06  7:57 ` [Qemu-devel] [PATCH v2 23/28] s390x/tcg: MVCIN: " David Hildenbrand
2019-09-11 21:35   ` Richard Henderson
2019-09-06  7:57 ` [Qemu-devel] [PATCH v2 24/28] s390x/tcg: MVN: " David Hildenbrand
2019-09-11 21:37   ` Richard Henderson
2019-09-06  7:57 ` [Qemu-devel] [PATCH v2 25/28] s390x/tcg: MVZ: " David Hildenbrand
2019-09-11 21:38   ` Richard Henderson
2019-09-06  7:57 ` [Qemu-devel] [PATCH v2 26/28] s390x/tcg: MVST: " David Hildenbrand
2019-09-11 21:52   ` Richard Henderson
2019-09-16 10:39     ` David Hildenbrand
2019-09-06  7:57 ` [Qemu-devel] [PATCH v2 27/28] s390x/tcg: MVO: " David Hildenbrand
2019-09-11 22:09   ` Richard Henderson
2019-09-06  7:57 ` [Qemu-devel] [PATCH v2 28/28] tests/tcg: target/s390x: Test MVO David Hildenbrand
2019-09-11 11:11 ` [Qemu-devel] [qemu-s390x] [PATCH v2 00/28] s390x/tcg: mem_helper: Fault-safe handling David Hildenbrand

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