diff options
Diffstat (limited to 'docs/specs/ppc-spapr-xive.rst')
| -rw-r--r-- | docs/specs/ppc-spapr-xive.rst | 10 |
1 files changed, 9 insertions, 1 deletions
diff --git a/docs/specs/ppc-spapr-xive.rst b/docs/specs/ppc-spapr-xive.rst index 6159bc6eed..7144347560 100644 --- a/docs/specs/ppc-spapr-xive.rst +++ b/docs/specs/ppc-spapr-xive.rst @@ -61,6 +61,11 @@ depend on the XIVE KVM capability of the host. On older kernels without XIVE KVM support, QEMU will use the emulated XIVE device as a fallback and on newer kernels (>=5.2), the KVM XIVE device. +XIVE native exploitation mode is not supported for KVM nested guests, +VMs running under a L1 hypervisor (KVM on pSeries). In that case, the +hypervisor will not advertise the KVM capability and QEMU will use the +emulated XIVE device, same as for older versions of KVM. + As a final refinement, the user can also switch the use of the KVM device with the machine option ``kernel_irqchip``. @@ -121,6 +126,9 @@ xics XICS KVM XICS emul. XICS KVM (1) QEMU warns with ``warning: kernel_irqchip requested but unavailable: IRQ_XIVE capability must be present for KVM`` + In some cases (old host kernels or KVM nested guests), one may hit a + QEMU/KVM incompatibility due to device destruction in reset. QEMU fails + with ``KVM is incompatible with ic-mode=dual,kernel-irqchip=on`` (2) QEMU fails with ``kernel_irqchip requested but unavailable: IRQ_XIVE capability must be present for KVM`` @@ -143,7 +151,7 @@ xics XICS KVM XICS emul. XICS KVM mode (XICS), either don't set the ic-mode machine property or try ic-mode=xics or ic-mode=dual`` (4) QEMU/KVM incompatibility due to device destruction in reset. QEMU fails - with ``KVM is too old to support ic-mode=dual,kernel-irqchip=on`` + with ``KVM is incompatible with ic-mode=dual,kernel-irqchip=on`` XIVE Device tree properties |