On Wed, Jan 29, 2025 at 04:47:28AM +0100, Marek Marczykowski-Górecki wrote: > On Tue, Jan 28, 2025 at 09:40:18PM -0600, Bjorn Helgaas wrote: > > I guess the code at [2] is running in user mode and uses Linux > > syscalls for config access? Is it straceable? > > Nope, it's running as the hypervisor and mediates Linux's access to the > hardware. In fact, Linux PV kernel (which dom0 is by default under Xen) > is running in ring 3... > > But I can add some more logging there. So I guess the hypervisor performs the config access on behalf of the Linux PV kernel? Obviously Linux thinks CRS/RRS SV is enabled, but I suppose all the lspci output is similarly based on whatever the hypervisor does, so how do we know the actual hardware config? > > > [2] https://xenbits.xen.org/gitweb/?p=xen.git;a=blob;f=xen/arch/x86/pv/emul-priv-op.c;h=70150c27227661baa253af8693ff00f2ab640a98;hb=HEAD#l295
