05bba0
From e4edeb73e3b9b1ba4efbf18ddb687fb210fd57f8 Mon Sep 17 00:00:00 2001
05bba0
From: John Snow <jsnow@redhat.com>
05bba0
Date: Fri, 26 Jun 2015 21:52:46 +0200
05bba0
Subject: [PATCH 1/2] ahci.c: mask unused flags when reading size PRDT DBC
05bba0
05bba0
Message-id: <1435355567-29641-2-git-send-email-jsnow@redhat.com>
05bba0
Patchwork-id: 66535
05bba0
O-Subject: [RHEL-7.2 qemu-kvm PATCH 1/2] ahci.c: mask unused flags when reading size PRDT DBC
05bba0
Bugzilla: 1205100
05bba0
RH-Acked-by: Kevin Wolf <kwolf@redhat.com>
05bba0
RH-Acked-by: Juan Quintela <quintela@redhat.com>
05bba0
RH-Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
05bba0
05bba0
From: Reza Jelveh <reza.jelveh@tuhh.de>
05bba0
05bba0
The data byte count(DBC) read from the description information is defined for
05bba0
bits 21:00. Bits 30:22 are reserved and bit 31 is the Interrupt on Completion
05bba0
(I) flag.
05bba0
05bba0
Completion interrupts are triggered after every transaction instead of on
05bba0
I-flag in QEMU. tbl_entry_size is a signed integer and improperly reading the
05bba0
DBC leads to a negative offset that causes sglist allocation to fail.
05bba0
05bba0
Signed-off-by: Reza Jelveh <reza.jelveh@tuhh.de>
05bba0
Reviewed-by: Alexander Graf <agraf@suse.de>
05bba0
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
05bba0
Reviewed-by: John Snow <jsnow@redhat.com>
05bba0
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
05bba0
(cherry picked from commit d02f8adc6d2a178bcbf77d0413f9a96fdbed53f0)
05bba0
Signed-off-by: John Snow <jsnow@redhat.com>
05bba0
Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
05bba0
---
05bba0
 hw/ide/ahci.c | 11 ++++++++---
05bba0
 hw/ide/ahci.h |  2 ++
05bba0
 2 files changed, 10 insertions(+), 3 deletions(-)
05bba0
05bba0
diff --git a/hw/ide/ahci.c b/hw/ide/ahci.c
05bba0
index 011e796..7f3927a 100644
05bba0
--- a/hw/ide/ahci.c
05bba0
+++ b/hw/ide/ahci.c
05bba0
@@ -635,6 +635,11 @@ static void ahci_write_fis_d2h(AHCIDevice *ad, uint8_t *cmd_fis)
05bba0
     }
05bba0
 }
05bba0
 
05bba0
+static int prdt_tbl_entry_size(const AHCI_SG *tbl)
05bba0
+{
05bba0
+    return (le32_to_cpu(tbl->flags_size) & AHCI_PRDT_SIZE_MASK) + 1;
05bba0
+}
05bba0
+
05bba0
 static int ahci_populate_sglist(AHCIDevice *ad, QEMUSGList *sglist, int offset)
05bba0
 {
05bba0
     AHCICmdHdr *cmd = ad->cur_cmd;
05bba0
@@ -675,7 +680,7 @@ static int ahci_populate_sglist(AHCIDevice *ad, QEMUSGList *sglist, int offset)
05bba0
         sum = 0;
05bba0
         for (i = 0; i < sglist_alloc_hint; i++) {
05bba0
             /* flags_size is zero-based */
05bba0
-            tbl_entry_size = (le32_to_cpu(tbl[i].flags_size) + 1);
05bba0
+            tbl_entry_size = prdt_tbl_entry_size(&tbl[i]);
05bba0
             if (offset <= (sum + tbl_entry_size)) {
05bba0
                 off_idx = i;
05bba0
                 off_pos = offset - sum;
05bba0
@@ -693,12 +698,12 @@ static int ahci_populate_sglist(AHCIDevice *ad, QEMUSGList *sglist, int offset)
05bba0
 
05bba0
         qemu_sglist_init(sglist, (sglist_alloc_hint - off_idx), ad->hba->dma);
05bba0
         qemu_sglist_add(sglist, le64_to_cpu(tbl[off_idx].addr + off_pos),
05bba0
-                        le32_to_cpu(tbl[off_idx].flags_size) + 1 - off_pos);
05bba0
+                        prdt_tbl_entry_size(&tbl[off_idx]) - off_pos);
05bba0
 
05bba0
         for (i = off_idx + 1; i < sglist_alloc_hint; i++) {
05bba0
             /* flags_size is zero-based */
05bba0
             qemu_sglist_add(sglist, le64_to_cpu(tbl[i].addr),
05bba0
-                            le32_to_cpu(tbl[i].flags_size) + 1);
05bba0
+                            prdt_tbl_entry_size(&tbl[i]));
05bba0
         }
05bba0
     }
05bba0
 
05bba0
diff --git a/hw/ide/ahci.h b/hw/ide/ahci.h
05bba0
index 85f37fe..47c0961 100644
05bba0
--- a/hw/ide/ahci.h
05bba0
+++ b/hw/ide/ahci.h
05bba0
@@ -201,6 +201,8 @@
05bba0
 
05bba0
 #define AHCI_COMMAND_TABLE_ACMD            0x40
05bba0
 
05bba0
+#define AHCI_PRDT_SIZE_MASK                0x3fffff
05bba0
+
05bba0
 #define IDE_FEATURE_DMA                    1
05bba0
 
05bba0
 #define READ_FPDMA_QUEUED                  0x60
05bba0
-- 
05bba0
1.8.3.1
05bba0