Re: Windows 10 Inaccessible Boot device starting 5.2.0-rc0

[Nick S]

I found the commit that breaks my VM. Anybody has any background on why it was done? The comments are fairly extensive, but they are Mac related and I am running Windows 10 with UEFI.  My VM is pc-q35-4.2 and this change definitely breaks Windows 10. Anything before I can check out, compile and it runs fine. Anything after this commit and it produces that boot device inaccessible error. Reverting this change on the current master also makes it work fine.

git diff af1b80ae56c9495999e8ccf7b70ef894378de642~ af1b80ae56c9495999e8ccf7b70ef894378de642

diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c
index b7bcbbbb2a..7a5a8b3521 100644
--- a/hw/i386/acpi-build.c
+++ b/hw/i386/acpi-build.c
@@ -1497,7 +1497,7 @@ build_dsdt(GArray *table_data, BIOSLinker *linker,
         dev = aml_device("PCI0");
         aml_append(dev, aml_name_decl("_HID", aml_eisaid("PNP0A03")));
         aml_append(dev, aml_name_decl("_ADR", aml_int(0)));
-        aml_append(dev, aml_name_decl("_UID", aml_int(1)));
+        aml_append(dev, aml_name_decl("_UID", aml_int(0)));
         aml_append(sb_scope, dev);
         aml_append(dsdt, sb_scope);
 
@@ -1512,7 +1512,7 @@ build_dsdt(GArray *table_data, BIOSLinker *linker,
         aml_append(dev, aml_name_decl("_HID", aml_eisaid("PNP0A08")));
         aml_append(dev, aml_name_decl("_CID", aml_eisaid("PNP0A03")));
         aml_append(dev, aml_name_decl("_ADR", aml_int(0)));
-        aml_append(dev, aml_name_decl("_UID", aml_int(1)));
+        aml_append(dev, aml_name_decl("_UID", aml_int(0)));
         aml_append(dev, build_q35_osc_method());
         aml_append(sb_scope, dev);
         aml_append(dsdt, sb_scope);

It looks like a regression issue in 5.2.x so I registered a bug for it: https://bugs.launchpad.net/qemu/+bug/1917565

On Sun, Feb 28, 2021 at 9:13 PM Nick S <nick.kvmhv@gmail.com> wrote:

I have a VM set up on a USB SSD drive that I assign directly using linux device (-blockdev '{"driver":"host_device","filename":"/dev/disk/by-id/scsi-1SanDisk_Extreme_SSD_20072F404043","aio":"native","node-name":"libvirt-2-storage","cache":{"direct":true,"no-flush":false},"auto-read-only":true,"discard":"unmap"}')

I've been using it for a few years now and recently decided to compile the most recent version of qemu to do some hacking. To my surprise, when I compiled the master branch, Windows failed to load with the "Boot Device Inaccessible" error. I went through tags in git and the latest tag that works is 5.1.0. On 5.2.0-rc0 I started getting this error. Was something changed recently for passing a linux block device as "raw"?

Thank you,

Nick