On Tue, Nov 22, 2016 at 04:43:52PM +0100, Paolo Bonzini wrote: > From: Peter Feiner <pfeiner@xxxxxxxxxx> > > [ upstream commit 4e59516a12a6ef6dcb660cb3a3f70c64bd60cfec, for 4.1.y only ] > > Between loading the new VMCS and enabling PML, the CPU was unpinned. > If the vCPU thread were migrated to another CPU in the interim (e.g., > due to preemption or sleeping alloc_page), then the VMWRITEs to enable > PML would target the wrong VMCS -- or no VMCS at all: > > [ 2087.266950] vmwrite error: reg 200e value 3fe1d52000 (err -506126336) > [ 2087.267062] vmwrite error: reg 812 value 1ff (err 511) > [ 2087.267125] vmwrite error: reg 401e value 12229c00 (err 304258048) > > This patch ensures that the VMCS remains current while enabling PML by > doing the VMWRITEs while the CPU is pinned. Allocation of the PML buffer > is hoisted out of the critical section. > > Signed-off-by: Peter Feiner <pfeiner@xxxxxxxxxx> > Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx> Tested-by: Greg Edwards <gedwards@xxxxxxx> -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html