On AMD family 17h processors, there is a feature called virtual GIF. This allows a nested hypervisor to preform a CLGI or STGI without needing to be intercepted by the host hypervisor. For more information about it please see:
AMD64 Architecture Programmer’s Manual Volume 2: System Programming http://support.amd.com/TechDocs/24593.pdf Section: Virtual GIF (Section 15.33.2) This patch series adds support to check for and enable the virtual GIF features if available. These patches were tested on an AMD family 17h (EPYC 7401) system. Changes since v2: - Removed else in vgif init code in vmcb.c due to it being unnecessary Changes since v1: - Change a test condition from if it had the vgif feature to if it's enabled in the vmcb - Update for the use of C99 bool type - Added else in vgif init code in vmcb.c Brian Woods (2): x86/svm: Add virtual GIF feature definition x86/svm: Add virtual GIF support xen/arch/x86/hvm/svm/nestedsvm.c | 7 ++++++- xen/arch/x86/hvm/svm/svm.c | 1 + xen/arch/x86/hvm/svm/vmcb.c | 9 +++++++++ xen/include/asm-x86/hvm/svm/svm.h | 2 ++ xen/include/asm-x86/hvm/svm/vmcb.h | 6 ++++-- 5 files changed, 22 insertions(+), 3 deletions(-) -- 2.11.0 _______________________________________________ Xen-devel mailing list Xen-devel@lists.xen.org https://lists.xen.org/xen-devel
