I have recently started playing with trusted launch to enable secure boot, it seem the Azure feature is taking memory out of the VM memory (50MB), I could not find any docs on this, is that normal/expected? I would expect that this kind of overhead comes out of Microsofts budget not the VMs memory :)

Example where it takes nearly 10% of the VM memory:

VM before enabling trusted launch (Standard_B1ls), 512MB memory as expected

# dmidecode -t memory # dmidecode 3.5 Getting SMBIOS data from sysfs. SMBIOS 3.1.0 present.

[...] Memory Device [...] Size: 512 MB [... side note here, their memory technology is out of spec :) ] Memory Technology: <OUT OF SPEC> [...]

After turning on Trusted Launch -- 462MB this means trusted launch steals nearly 10% of memory (9,765625% if you want to be exact)

# dmidecode -t memory # dmidecode 3.5 Getting SMBIOS data from sysfs. SMBIOS 3.1.0 present.

Handle 0x0006, DMI type 16, 23 bytes Physical Memory Array [...] Number Of Devices: 2 [...] Handle 0x0007, DMI type 17, 92 bytes Memory Device Array Handle: 0x0006 [...] Size: 26 MB [...] Locator: M0001 [...] Handle 0x000A, DMI type 17, 92 bytes Memory Device Array Handle: 0x0006 [...] Size: 436 MB [...] Locator: M0002 [...]