Bug 1428641

Description of problem:

   Physical block size change to "512" after installation with the size "4096" for windows guest.

Version-Release number of selected component (if applicable):
 kernel version:3.10.0-566.el7.x86_64
 qemu-kvm-rhev version：qemu-kvm-rhev-2.8.0-5.el7.x86_64

How reproducible:

100%

Steps to Reproduce:
1.Create a 20G qcow2 image:"check_block_size_image.qcow2"
  
2.Install a Win2016 guest with physical block size "4096", cmds as bellow:
/usr/libexec/qemu-kvm \
-name 'avocado-vt-vm1'  \
-sandbox off  \
-machine pc  \
-nodefaults  \
-vga std  \
-chardev socket,id=qmp_id_qmpmonitor1,path=/var/tmp/monitor-qmpmonitor1-20170302-023157-EI3EbutK,server,nowait \
-mon chardev=qmp_id_qmpmonitor1,mode=control  \
-chardev socket,id=qmp_id_catch_monitor,path=/var/tmp/monitor-catch_monitor-20170302-023157-EI3EbutK,server,nowait \
-mon chardev=qmp_id_catch_monitor,mode=control \
-device pvpanic,ioport=0x505,id=idV0oEZ0  \
-chardev socket,id=serial_id_serial0,path=/var/tmp/serial-serial0-20170302-023157-EI3EbutK,server,nowait \
-device isa-serial,chardev=serial_id_serial0  \
-chardev socket,id=seabioslog_id_20170302-023157-EI3EbutK,path=/var/tmp/seabios-20170302-023157-EI3EbutK,server,nowait \
-device isa-debugcon,chardev=seabioslog_id_20170302-023157-EI3EbutK,iobase=0x402 \
-device ich9-usb-ehci1,id=usb1,addr=1d.7,multifunction=on,bus=pci.0 \
-device ich9-usb
uhci1,id=usb1.0,multifunction=on,masterbus=usb1.0,addr=1d.0,firstport=0,bus=pci.0 \
-device ich9-usb-uhci2,id=usb1.1,multifunction=on,masterbus=usb1.0,addr=1d.2,firstport=2,bus=pci.0 \
-device ich9-usb-uhci3,id=usb1.2,multifunction=on,masterbus=usb1.0,addr=1d.4,firstport=4,bus=pci.0 \
-drive id=drive_stg,if=none,snapshot=off,aio=native,cache=none,format=qcow2,file=/home/kvm_autotest_root/images/check_block_size_image.qcow2 \
-device virtio-blk-pci,id=stg,drive=drive_stg,logical_block_size=512,physical_block_size=4096,bootindex=0,serial=TARGET_DISK0,bus=pci.0,addr=03 \
-device virtio-net-pci,mac=9a:56:57:58:59:5a,id=idp8F0oX,vectors=4,netdev=idRDZp3I,bus=pci.0,addr=04  \
-netdev tap,id=idRDZp3I,vhost=on \
-m 8192  \
-smp 8,maxcpus=8,cores=4,threads=1,sockets=2  \
-cpu 'SandyBridge',+kvm_pv_unhalt,hv_spinlocks=0x1fff,hv_vapic,hv_time \
-drive id=drive_cd1,if=none,snapshot=off,aio=native,cache=none,media=cdrom,file=/home/kvm_autotest_root/iso/ISO/Win2016/en_windows_server_2016_x64_dvd_9327751.iso \
-device ide-cd,id=cd1,drive=drive_cd1,bootindex=1,bus=ide.0,unit=0 \
-drive id=drive_winutils,if=none,snapshot=off,aio=native,cache=none,media=cdrom,file=/home/kvm_autotest_root/iso/windows/winutils.iso \
-device ide-cd,id=winutils,drive=drive_winutils,bootindex=2,bus=ide.0,unit=1 \
-drive id=drive_unattended,if=none,snapshot=off,aio=native,cache=none,media=cdrom,file=/home/kvm_autotest_root/images/win2016-64/autounattend.iso \
-device ide-cd,id=unattended,drive=drive_unattended,bootindex=3,bus=ide.1,unit=0 \
-drive id=drive_virtio,if=none,snapshot=off,aio=native,cache=none,media=cdrom,file=/home/kvm_autotest_root/iso/windows/virtio-win-1.9.0-3.el7.iso \
-device ide-cd,id=virtio,drive=drive_virtio,bootindex=4,bus=ide.1,unit=1 \
-device usb-tablet,id=usb-tablet1,bus=usb1.0,port=1  \
-vnc :0  \
-rtc base=localtime,clock=host,driftfix=slew  \
-boot order=cdn,once=d,menu=off,strict=off \
-enable-kvm
  
2.After the installation finished, check physical block size in guest.
  (Win2016)# powershell "get-disk|format list"

Actual results:
After step2, the physical block size is "512"

Expected results:
Physical block size should be "4096"

Additional info: