On 24/02/2023 6:50 pm, Xenia Ragiadakou wrote: > Create two new private headers in arch/x86/hvm/vmx called vmx.h and pi.h. > Move all the definitions and declarations that are used solely by vmx code > into the private vmx.h, apart from the ones related to posted interrupts that > are moved into pi.h. > > EPT related declarations and definitions stay in asm/hvm/vmx/vmx.h because > they are used in arch/x86/mm and drivers/passthrough/vtd. > > Also, __vmread(), used in arch/x86/cpu, and consequently the opcodes stay in > asm/hvm/vmx/vmx.h.
Every time I read the vpmu code, I get increasingly sad. That is dangerously unsafe, and comes with a chance of exploding completely. That __vmread() is in NMI context, which means `current` isn't safe to deference (we might hit in the middle of a context switch), and more generally there's no guarantee that the loaded VMCS is the one associated with `current` (we might hit in the middle of a remote VMCS access). vpmu is generally not supported, and BTS needs further custom enablement because it is only useable with a custom bus analyser. The __vmread() needs deleting - its absolutely not safe to say. I'm tempted to hardwire the return 0, and punt the problem to whomever next uses BTS. Alternatively, MSR_DBGCTL needs wiring into the hvm_get_reg() infrastructure, but I'm not convinced this will actually work in either of the two problem cases above, hence preferring the previous option. Thoughts? ~Andrew
