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Blame SOURCES/kvm-scsi-generic-avoid-invalid-access-to-struct-when-emu.patch

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From 00c5ee2a99e03dd349061981d6560975ab9707d0 Mon Sep 17 00:00:00 2001
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From: Paolo Bonzini <pbonzini@redhat.com>
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Date: Thu, 20 Dec 2018 12:31:02 +0000
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Subject: [PATCH 7/8] scsi-generic: avoid invalid access to struct when
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 emulating block limits
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MIME-Version: 1.0
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Content-Type: text/plain; charset=UTF-8
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Content-Transfer-Encoding: 8bit
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RH-Author: Paolo Bonzini <pbonzini@redhat.com>
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Message-id: <20181220123103.29579-8-pbonzini@redhat.com>
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Patchwork-id: 83718
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O-Subject: [PATCH 7/8] scsi-generic: avoid invalid access to struct when emulating block limits
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Bugzilla: 1639957
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RH-Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
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RH-Acked-by: Philippe Mathieu-Daudé <philmd@redhat.com>
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RH-Acked-by: Kevin Wolf <kwolf@redhat.com>
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RH-Acked-by: Laurent Vivier <lvivier@redhat.com>
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Emulation of the block limits VPD page called back into scsi-disk.c,
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which however expected the request to be for a SCSIDiskState and
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accessed a scsi-generic device outside the bounds of its struct
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(namely to retrieve s->max_unmap_size and s->max_io_size).
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To avoid this, move the emulation code to a separate function that
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takes a new SCSIBlockLimits struct and marshals it into the VPD
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response format.
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Reported-by: Max Reitz <mreitz@redhat.com>
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Reviewed-by: Max Reitz <mreitz@redhat.com>
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Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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(cherry picked from commit 3d4a8bf0eed68a781e06118e4d1df6e2f106a1f2)
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Signed-off-by: Danilo C. L. de Paula <ddepaula@redhat.com>
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---
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 hw/scsi/Makefile.objs       |  2 +-
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 hw/scsi/emulation.c         | 42 +++++++++++++++++++++
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 hw/scsi/scsi-disk.c         | 92 ++++++++++-----------------------------------
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 hw/scsi/scsi-generic.c      | 35 ++++++++++++-----
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 include/hw/scsi/emulation.h | 16 ++++++++
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 include/hw/scsi/scsi.h      |  1 -
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 6 files changed, 104 insertions(+), 84 deletions(-)
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 create mode 100644 hw/scsi/emulation.c
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 create mode 100644 include/hw/scsi/emulation.h
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diff --git a/hw/scsi/Makefile.objs b/hw/scsi/Makefile.objs
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index b188f72..c4f249a 100644
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--- a/hw/scsi/Makefile.objs
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+++ b/hw/scsi/Makefile.objs
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@@ -1,4 +1,4 @@
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-common-obj-y += scsi-disk.o
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+common-obj-y += scsi-disk.o emulation.o
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 common-obj-y += scsi-generic.o scsi-bus.o
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 common-obj-$(CONFIG_LSI_SCSI_PCI) += lsi53c895a.o
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 common-obj-$(CONFIG_MPTSAS_SCSI_PCI) += mptsas.o mptconfig.o mptendian.o
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diff --git a/hw/scsi/emulation.c b/hw/scsi/emulation.c
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new file mode 100644
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index 0000000..06d62f3
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--- /dev/null
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+++ b/hw/scsi/emulation.c
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@@ -0,0 +1,42 @@
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+#include "qemu/osdep.h"
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+#include "qemu/units.h"
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+#include "qemu/bswap.h"
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+#include "hw/scsi/emulation.h"
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+
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+int scsi_emulate_block_limits(uint8_t *outbuf, const SCSIBlockLimits *bl)
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+{
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+    /* required VPD size with unmap support */
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+    memset(outbuf, 0, 0x3c);
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+
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+    outbuf[0] = bl->wsnz; /* wsnz */
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+
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+    if (bl->max_io_sectors) {
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+        /* optimal transfer length granularity.  This field and the optimal
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+         * transfer length can't be greater than maximum transfer length.
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+         */
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+        stw_be_p(outbuf + 2, MIN(bl->min_io_size, bl->max_io_sectors));
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+
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+        /* maximum transfer length */
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+        stl_be_p(outbuf + 4, bl->max_io_sectors);
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+
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+        /* optimal transfer length */
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+        stl_be_p(outbuf + 8, MIN(bl->opt_io_size, bl->max_io_sectors));
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+    } else {
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+        stw_be_p(outbuf + 2, bl->min_io_size);
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+        stl_be_p(outbuf + 8, bl->opt_io_size);
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+    }
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+
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+    /* max unmap LBA count */
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+    stl_be_p(outbuf + 16, bl->max_unmap_sectors);
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+
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+    /* max unmap descriptors */
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+    stl_be_p(outbuf + 20, bl->max_unmap_descr);
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+
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+    /* optimal unmap granularity; alignment is zero */
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+    stl_be_p(outbuf + 24, bl->unmap_sectors);
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+
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+    /* max write same size, make it the same as maximum transfer length */
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+    stl_be_p(outbuf + 36, bl->max_io_sectors);
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+
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+    return 0x3c;
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+}
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diff --git a/hw/scsi/scsi-disk.c b/hw/scsi/scsi-disk.c
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index b8a27d6..a20ef91 100644
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--- a/hw/scsi/scsi-disk.c
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+++ b/hw/scsi/scsi-disk.c
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@@ -32,6 +32,7 @@ do { printf("scsi-disk: " fmt , ## __VA_ARGS__); } while (0)
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 #include "qapi/error.h"
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 #include "qemu/error-report.h"
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 #include "hw/scsi/scsi.h"
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+#include "hw/scsi/emulation.h"
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 #include "scsi/constants.h"
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 #include "sysemu/sysemu.h"
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 #include "sysemu/block-backend.h"
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@@ -585,7 +586,7 @@ static uint8_t *scsi_get_buf(SCSIRequest *req)
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     return (uint8_t *)r->iov.iov_base;
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 }
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-int scsi_disk_emulate_vpd_page(SCSIRequest *req, uint8_t *outbuf)
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+static int scsi_disk_emulate_vpd_page(SCSIRequest *req, uint8_t *outbuf)
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 {
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     SCSIDiskState *s = DO_UPCAST(SCSIDiskState, qdev, req->dev);
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     uint8_t page_code = req->cmd.buf[2];
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@@ -687,89 +688,36 @@ int scsi_disk_emulate_vpd_page(SCSIRequest *req, uint8_t *outbuf)
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     }
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     case 0xb0: /* block limits */
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     {
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-        unsigned int unmap_sectors =
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-            s->qdev.conf.discard_granularity / s->qdev.blocksize;
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-        unsigned int min_io_size =
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-            s->qdev.conf.min_io_size / s->qdev.blocksize;
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-        unsigned int opt_io_size =
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-            s->qdev.conf.opt_io_size / s->qdev.blocksize;
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-        unsigned int max_unmap_sectors =
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-            s->max_unmap_size / s->qdev.blocksize;
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-        unsigned int max_io_sectors =
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-            s->max_io_size / s->qdev.blocksize;
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+        SCSIBlockLimits bl = {};
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         if (s->qdev.type == TYPE_ROM) {
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             DPRINTF("Inquiry (EVPD[%02X] not supported for CDROM\n",
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                     page_code);
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             return -1;
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         }
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+        bl.wsnz = 1;
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+        bl.unmap_sectors =
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+            s->qdev.conf.discard_granularity / s->qdev.blocksize;
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+        bl.min_io_size =
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+            s->qdev.conf.min_io_size / s->qdev.blocksize;
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+        bl.opt_io_size =
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+            s->qdev.conf.opt_io_size / s->qdev.blocksize;
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+        bl.max_unmap_sectors =
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+            s->max_unmap_size / s->qdev.blocksize;
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+        bl.max_io_sectors =
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+            s->max_io_size / s->qdev.blocksize;
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+        /* 255 descriptors fit in 4 KiB with an 8-byte header */
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+        bl.max_unmap_descr = 255;
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+
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         if (s->qdev.type == TYPE_DISK) {
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             int max_transfer_blk = blk_get_max_transfer(s->qdev.conf.blk);
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             int max_io_sectors_blk =
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                 max_transfer_blk / s->qdev.blocksize;
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-            max_io_sectors =
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-                MIN_NON_ZERO(max_io_sectors_blk, max_io_sectors);
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-
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-            /* min_io_size and opt_io_size can't be greater than
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-             * max_io_sectors */
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-            if (min_io_size) {
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-                min_io_size = MIN(min_io_size, max_io_sectors);
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-            }
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-            if (opt_io_size) {
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-                opt_io_size = MIN(opt_io_size, max_io_sectors);
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-            }
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+            bl.max_io_sectors =
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+                MIN_NON_ZERO(max_io_sectors_blk, bl.max_io_sectors);
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         }
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-        /* required VPD size with unmap support */
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-        buflen = 0x40;
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-        memset(outbuf + 4, 0, buflen - 4);
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-
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-        outbuf[4] = 0x1; /* wsnz */
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-
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-        /* optimal transfer length granularity */
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-        outbuf[6] = (min_io_size >> 8) & 0xff;
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-        outbuf[7] = min_io_size & 0xff;
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-
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-        /* maximum transfer length */
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-        outbuf[8] = (max_io_sectors >> 24) & 0xff;
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-        outbuf[9] = (max_io_sectors >> 16) & 0xff;
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-        outbuf[10] = (max_io_sectors >> 8) & 0xff;
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-        outbuf[11] = max_io_sectors & 0xff;
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-
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-        /* optimal transfer length */
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-        outbuf[12] = (opt_io_size >> 24) & 0xff;
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-        outbuf[13] = (opt_io_size >> 16) & 0xff;
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-        outbuf[14] = (opt_io_size >> 8) & 0xff;
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-        outbuf[15] = opt_io_size & 0xff;
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-
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-        /* max unmap LBA count, default is 1GB */
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-        outbuf[20] = (max_unmap_sectors >> 24) & 0xff;
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-        outbuf[21] = (max_unmap_sectors >> 16) & 0xff;
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-        outbuf[22] = (max_unmap_sectors >> 8) & 0xff;
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-        outbuf[23] = max_unmap_sectors & 0xff;
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-
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-        /* max unmap descriptors, 255 fit in 4 kb with an 8-byte header */
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-        outbuf[24] = 0;
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-        outbuf[25] = 0;
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-        outbuf[26] = 0;
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-        outbuf[27] = 255;
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-
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-        /* optimal unmap granularity */
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-        outbuf[28] = (unmap_sectors >> 24) & 0xff;
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-        outbuf[29] = (unmap_sectors >> 16) & 0xff;
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-        outbuf[30] = (unmap_sectors >> 8) & 0xff;
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-        outbuf[31] = unmap_sectors & 0xff;
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-
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-        /* max write same size */
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-        outbuf[36] = 0;
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-        outbuf[37] = 0;
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-        outbuf[38] = 0;
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-        outbuf[39] = 0;
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-
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-        outbuf[40] = (max_io_sectors >> 24) & 0xff;
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-        outbuf[41] = (max_io_sectors >> 16) & 0xff;
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-        outbuf[42] = (max_io_sectors >> 8) & 0xff;
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-        outbuf[43] = max_io_sectors & 0xff;
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+        buflen += scsi_emulate_block_limits(outbuf + buflen, &bl);
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         break;
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     }
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     case 0xb1: /* block device characteristics */
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diff --git a/hw/scsi/scsi-generic.c b/hw/scsi/scsi-generic.c
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index 6d6db69..f218cef 100644
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--- a/hw/scsi/scsi-generic.c
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+++ b/hw/scsi/scsi-generic.c
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@@ -16,6 +16,7 @@
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 #include "qemu-common.h"
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 #include "qemu/error-report.h"
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 #include "hw/scsi/scsi.h"
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+#include "hw/scsi/emulation.h"
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 #include "sysemu/block-backend.h"
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 #include "sysemu/blockdev.h"
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@@ -182,7 +183,7 @@ static void scsi_handle_inquiry_reply(SCSIGenericReq *r, SCSIDevice *s)
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             /* Also take care of the opt xfer len. */
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             stl_be_p(&r->buf[12],
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                     MIN_NON_ZERO(max_transfer, ldl_be_p(&r->buf[12])));
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-        } else if (page == 0x00 && s->needs_vpd_bl_emulation) {
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+        } else if (s->needs_vpd_bl_emulation && page == 0x00) {
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             /*
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              * Now we're capable of supplying the VPD Block Limits
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              * response if the hardware can't. Add it in the INQUIRY
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@@ -210,9 +211,24 @@ static void scsi_handle_inquiry_reply(SCSIGenericReq *r, SCSIDevice *s)
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     }
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 }
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-static int scsi_emulate_block_limits(SCSIGenericReq *r)
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+static int scsi_generic_emulate_block_limits(SCSIGenericReq *r, SCSIDevice *s)
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 {
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-    r->buflen = scsi_disk_emulate_vpd_page(&r->req, r->buf);
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+    int len;
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+    uint8_t buf[64];
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+
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+    SCSIBlockLimits bl = {
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+        .max_io_sectors = blk_get_max_transfer(s->conf.blk) / s->blocksize
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+    };
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+
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+    memset(r->buf, 0, r->buflen);
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+    stb_p(buf, s->type);
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+    stb_p(buf + 1, 0xb0);
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+    len = scsi_emulate_block_limits(buf + 4, &bl);
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+    assert(len <= sizeof(buf) - 4);
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+    stw_be_p(buf + 2, len);
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+
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+    memcpy(r->buf, buf, MIN(r->buflen, len + 4));
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+
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     r->io_header.sb_len_wr = 0;
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     /*
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@@ -254,13 +270,12 @@ static void scsi_read_complete(void * opaque, int ret)
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      * resulted in sense error but would need emulation.
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      * In this case, emulate a valid VPD response.
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      */
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-    if (s->needs_vpd_bl_emulation) {
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-        int is_vpd_bl = r->req.cmd.buf[0] == INQUIRY &&
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-                         r->req.cmd.buf[1] & 0x01 &&
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-                         r->req.cmd.buf[2] == 0xb0;
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-
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-        if (is_vpd_bl && sg_io_sense_from_errno(-ret, &r->io_header, &sense)) {
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-            len = scsi_emulate_block_limits(r);
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+    if (s->needs_vpd_bl_emulation &&
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+        r->req.cmd.buf[0] == INQUIRY &&
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+        (r->req.cmd.buf[1] & 0x01) &&
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+        r->req.cmd.buf[2] == 0xb0) {
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+        if (sg_io_sense_from_errno(-ret, &r->io_header, &sense)) {
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+            len = scsi_generic_emulate_block_limits(r, s);
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             /*
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              * No need to let scsi_read_complete go on and handle an
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              * INQUIRY VPD BL request we created manually.
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diff --git a/include/hw/scsi/emulation.h b/include/hw/scsi/emulation.h
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new file mode 100644
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index 0000000..09fba1f
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--- /dev/null
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+++ b/include/hw/scsi/emulation.h
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@@ -0,0 +1,16 @@
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+#ifndef HW_SCSI_EMULATION_H
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+#define HW_SCSI_EMULATION_H 1
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+
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+typedef struct SCSIBlockLimits {
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+    bool wsnz;
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+    uint16_t min_io_size;
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+    uint32_t max_unmap_descr;
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+    uint32_t opt_io_size;
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+    uint32_t max_unmap_sectors;
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+    uint32_t unmap_sectors;
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+    uint32_t max_io_sectors;
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+} SCSIBlockLimits;
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+
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+int scsi_emulate_block_limits(uint8_t *outbuf, const SCSIBlockLimits *bl);
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+
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+#endif
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diff --git a/include/hw/scsi/scsi.h b/include/hw/scsi/scsi.h
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index ee3a411..acef25f 100644
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--- a/include/hw/scsi/scsi.h
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+++ b/include/hw/scsi/scsi.h
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@@ -189,7 +189,6 @@ void scsi_device_report_change(SCSIDevice *dev, SCSISense sense);
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 void scsi_device_unit_attention_reported(SCSIDevice *dev);
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 void scsi_generic_read_device_inquiry(SCSIDevice *dev);
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 int scsi_device_get_sense(SCSIDevice *dev, uint8_t *buf, int len, bool fixed);
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-int scsi_disk_emulate_vpd_page(SCSIRequest *req, uint8_t *outbuf);
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 int scsi_SG_IO_FROM_DEV(BlockBackend *blk, uint8_t *cmd, uint8_t cmd_size,
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                         uint8_t *buf, uint8_t buf_size);
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 SCSIDevice *scsi_device_find(SCSIBus *bus, int channel, int target, int lun);
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-- 
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1.8.3.1
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