On Wed, May 09, 2018 at 05:13:01PM +0100, Dave P Martin wrote: > This patch adds SVE context saving to the hyp FPSIMD context switch > path. This means that it is no longer necessary to save the host > SVE state in advance of entering the guest, when in use. > > In order to avoid adding pointless complexity to the code, VHE is > assumed if SVE is in use. VHE is an architectural prerequisite for > SVE, so there is no good reason to turn CONFIG_ARM64_VHE off in > kernels that support both SVE and KVM. > > Historically, software models exist that can expose the > architecturally invalid configuration of SVE without VHE, so if > this situation is detected at kvm_init() time then KVM will be > disabled. > > Signed-off-by: Dave Martin <Dave.Martin@xxxxxxx> > Reviewed-by: Christoffer Dall <christoffer.dall@xxxxxxx> > Acked-by: Marc Zyngier <marc.zyngier@xxxxxxx> > --- > arch/arm64/Kconfig | 7 +++++++ > arch/arm64/kvm/fpsimd.c | 1 - > arch/arm64/kvm/hyp/switch.c | 20 +++++++++++++++++++- > virt/kvm/arm/arm.c | 18 ++++++++++++++++++ > 4 files changed, 44 insertions(+), 2 deletions(-) > > diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig > index eb2cf49..b0d3820 100644 > --- a/arch/arm64/Kconfig > +++ b/arch/arm64/Kconfig > @@ -1130,6 +1130,7 @@ endmenu > config ARM64_SVE > bool "ARM Scalable Vector Extension support" > default y > + depends on !KVM || ARM64_VHE > help > The Scalable Vector Extension (SVE) is an extension to the AArch64 > execution state which complements and extends the SIMD functionality > @@ -1155,6 +1156,12 @@ config ARM64_SVE > booting the kernel. If unsure and you are not observing these > symptoms, you should assume that it is safe to say Y. > > + CPUs that support SVE are architecturally required to support the > + Virtualization Host Extensions (VHE), so the kernel makes no > + provision for supporting SVE alongside KVM without VHE enabled. > + Thus, you will need to enable CONFIG_ARM64_VHE if you want to support > + KVM in the same kernel image. Acked-by: Catalin Marinas <catalin.marinas@xxxxxxx> _______________________________________________ kvmarm mailing list kvmarm@xxxxxxxxxxxxxxxxxxxxx https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
