In the Linux kernel, the following vulnerability has been resolved:

KVM: arm64: nv: Inject SEA if guest VNCR isn't normal memory

When constructing an L1 VNCR mapping, KVM unconditionally uses cacheable memory attributes, even if the underlying PFN isn't memory. This gets particularly hairy if the endpoint doesn't support cacheable memory attributes, potentially throwing an SError on writeback...

While KVM does permit cacheable memory attributes on certain PFNMAP VMAs, kvmtranslatevncr() isn't currently grabbing the VMA. So do the simpler thing for now and just reject everything that isn't memory.

In the Linux kernel, the following vulnerability has been resolved:

KVM: nVMX: Always flush vpid02 on first use

Make sure vpid02 is always flushed on first use by setting lastvpid=0 when allocating vpid02. nestedvmxtransitiontlbflush() will always detect a VPID change on first VM-Enter after VMXON, because VPID=0 in vmcs12 is not allowed if L1 enables VPID.

This avoids using stale TLB entries from a previous lifetime of the VPID, that might have been associated with a different vCPU (or a completely different VM).

Note that lastvpid is already being initialized as 0 when the vCPU is created, but it is not reset when vpid02 is freed on VMXOFF. Hence, the problem can only occur if L1 does VMXOFF -> VMXON, runs an L2, and KVM happens to reuse a VPID that has TLB entries on the physical CPU.