Hi All,

                Setup:

                - x86 based platforms, running Yocto-Linux with QEMU/KVM to launch our FreeBSD VM's

 

                Issue in brief:

                I’m encountering an issue in one of our platforms, while accessing the SMBIOSTable with SMP Enabled 64-bit FreeBSD kernel

 

                - This issue is NOT observed on all our platforms.

                - just seeing it on a specific platform, which has changes to the HostOS BIOS

 

                 The FreeBSD VM's access the SMBIOS table, where the smbios is shared to the VM using

                <smbios mode='host'/>

 

                While enabling SMP on 64-bit FreeBSD Kernel, I see that the SMBIOSTable is accessed at different location compared to the address shared when SMP is disabled.

 

                === with 1 vCPU to FreeBSD (No SMP) ====

addr found @ 0x800f0c20

 SMBIOS map : 800f0c40 f0c40  kva 0 > 140 {800f0c40, f0c40  <----> virtual address(va), physical address(pa) }

 SMBIOS map  800f0c40 f0c40  page num 0  140

 SMBIOS mapped 800f0c40 f0c40 0xffff807fffc00780

Found SMBIOS Ver 2.8 at 0xffffffff800f0c40 - Beyond mapped region

smbios: Found SMBIOS Ver 2.8 at 0xffffffff800f0c20

smbios: Table at 0xffffffff800f0c40 len 568

Fast boot:0

 

                === with 2 vCPU to FreeBSD (SMP enabled) ====

                addr found @ 0x800f0e40

SMBIOS map :  fa1ffd80 7a1ffd80  kva 3d0 > 140   {fa1ffd80, 7a1ffd80 <----> va, pa }

Found SMBIOS Ver 2.8 at 0xfffffffffa1ffd80 - Beyond mapped region

Fast boot:0

kernel trap 12 with interrupts disabled è PANIC PANIC PANIC

 

 

                The following are couple of questions:

1. why is that the SMBIOSTable gets mapped at different addresses when launching the VM with and without SMP (SMP with 2 vCPUs

2. Is there a way to PIN the SMBIOSTable for the VM ? This probably will help address the issue

3. The issue is seen only with a specific platform. While, SMP in 64-bit OCCAM works fine on many other platforms. Does it mean, it is an issue specific to the bios release for Porter?

4 .I could address the issue by using

           please suggest ways to identify the problem and any potential solutions

 

thanks in advance & rgds,

Sundareswaram