Blame SOURCES/kvm-scsi-generic-Fix-emulated-block-limits-VPD-page.patch

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From a9a4dfdd6312e192e9134d46edfac4c1b1bfa63d Mon Sep 17 00:00:00 2001
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From: Kevin Wolf <kwolf@redhat.com>
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Date: Mon, 22 Aug 2022 14:53:20 +0200
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Subject: [PATCH] scsi-generic: Fix emulated block limits VPD page
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RH-Author: Kevin Wolf <kwolf@redhat.com>
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RH-MergeRequest: 212: scsi-generic: Fix emulated block limits VPD page
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RH-Commit: [1/1] d3ba6b2e03039043716ddc6b7d4a424d92249081
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RH-Bugzilla: 2120279
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RH-Acked-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
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RH-Acked-by: Hanna Reitz <hreitz@redhat.com>
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RH-Acked-by: Paolo Bonzini <pbonzini@redhat.com>
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RH-Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
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Commits 01ef8185b80 amd 24b36e9813e updated the way that the maximum
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transfer length is calculated for patching block limits VPD page in an
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INQUIRY response.
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The same updates also need to be made for the case where the host device
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does not support the block limits VPD page at all and we emulate the
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whole page.
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Without this fix, on host block devices a maximum transfer length of
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(INT_MAX - sector_size) bytes is advertised to the guest, resulting in
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I/O errors when a request that exceeds the host limits is made by the
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guest. (Prior to commit 24b36e9813e, this code path would use the
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max_transfer value from the host instead of INT_MAX, but still miss the
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fix from 01ef8185b80 where max_transfer is also capped to max_iov
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host pages, so it would be less wrong, but still wrong.)
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Cc: qemu-stable@nongnu.org
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Buglink: https://bugzilla.redhat.com/show_bug.cgi?id=2096251
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Fixes: 01ef8185b809af9d287e1a03a3f9d8ea8231118a
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Fixes: 24b36e9813ec15da7db62e3b3621730710c5f020
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Signed-off-by: Kevin Wolf <kwolf@redhat.com>
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Message-Id: <20220822125320.48257-1-kwolf@redhat.com>
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Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
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Signed-off-by: Kevin Wolf <kwolf@redhat.com>
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(cherry picked from commit 51e15194b0a091e5c40aab2eb234a1d36c5c58ee)
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Resolved conflict: qemu_real_host_page_size() is a getter function in
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current upstream, but still just a public global variable downstream.
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Signed-off-by: Kevin Wolf <kwolf@redhat.com>
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---
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 hw/scsi/scsi-generic.c | 21 ++++++++++++++-------
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 1 file changed, 14 insertions(+), 7 deletions(-)
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diff --git a/hw/scsi/scsi-generic.c b/hw/scsi/scsi-generic.c
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index 0306ccc7b1..3742899839 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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@@ -147,6 +147,18 @@ static int execute_command(BlockBackend *blk,
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     return 0;
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 }
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+static uint64_t calculate_max_transfer(SCSIDevice *s)
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+{
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+    uint64_t max_transfer = blk_get_max_hw_transfer(s->conf.blk);
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+    uint32_t max_iov = blk_get_max_hw_iov(s->conf.blk);
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+
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+    assert(max_transfer);
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+    max_transfer = MIN_NON_ZERO(max_transfer,
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+                                max_iov * qemu_real_host_page_size);
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+
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+    return max_transfer / s->blocksize;
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+}
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+
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 static int scsi_handle_inquiry_reply(SCSIGenericReq *r, SCSIDevice *s, int len)
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 {
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     uint8_t page, page_idx;
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@@ -179,12 +191,7 @@ static int scsi_handle_inquiry_reply(SCSIGenericReq *r, SCSIDevice *s, int len)
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         (r->req.cmd.buf[1] & 0x01)) {
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         page = r->req.cmd.buf[2];
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         if (page == 0xb0) {
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-            uint64_t max_transfer = blk_get_max_hw_transfer(s->conf.blk);
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-            uint32_t max_iov = blk_get_max_hw_iov(s->conf.blk);
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-
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-            assert(max_transfer);
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-            max_transfer = MIN_NON_ZERO(max_transfer, max_iov * qemu_real_host_page_size)
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-                / s->blocksize;
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+            uint64_t max_transfer = calculate_max_transfer(s);
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             stl_be_p(&r->buf[8], max_transfer);
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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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@@ -230,7 +237,7 @@ static int scsi_generic_emulate_block_limits(SCSIGenericReq *r, SCSIDevice *s)
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     uint8_t buf[64];
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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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+        .max_io_sectors = calculate_max_transfer(s),
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     };
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     memset(r->buf, 0, r->buflen);
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-- 
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2.35.3
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