On 23/08/2017 16:57, Janakarajan Natarajan wrote: > This patchset adds support for the Virtual GIF (vGIF) feature. This > feature allows the STGI and CLGI instructions to be executed in the > Guest Mode and not require a #VMEXIT. With this, virtual interrupts > can be controlled in the Guest Mode while still allowing physical > interrupts to be intercepted by the hypervisor. > > In order to provide this ability, two new bits are added to the VMCB > at offset 60h: > > * Bit 9 - VGIF value > : 0 -> Virtual interrupts are masked > : 1 -> Virtual interrupts are unmasked > > * Bit 25 - AMD Virtual GIF enabled for this guest > : 0 -> Disabled > : 1 -> Enabled > > When a VMRUN is executed and Bit 25 is set, the processor uses Bit 9 > as the starting value of the virtual GIF. It then provides masking > capability for when virtual interrupts are taken. Bit 9 is writeable > by the hypervisor and loaded on VMRUN and saved on #VMEXIT. STGI/CLGI > executed in the Guest Mode sets or clears the virtual GIF. > > The advantage of this feature will be the greatly reduced number of > world switches to support the STGI and CLGI instructions by the > outermost hypervisor at Current Privilege Level (CPL) 0. > > This has been tested with Xen, Hyper-V and KVM as the nested hypervisor. > > v1->v2: > > * Updated patch description and changed cpufeature definition to be similar > to AMD documentation. > > * Updated NMI logic. STGI intercept added to assit in opening NMI window. > Suggested by Radim. Applied, thanks. Paolo > Janakarajan Natarajan (2): > KVM: SVM: Add Virtual GIF feature definition > KVM: SVM: Enable Virtual GIF feature > > arch/x86/include/asm/cpufeatures.h | 1 + > arch/x86/include/asm/svm.h | 6 ++++ > arch/x86/kvm/svm.c | 62 +++++++++++++++++++++++++++++++++----- > 3 files changed, 62 insertions(+), 7 deletions(-) >
