Re: [PATCH v3 2/7] qemu: check if s390 secure guest support is enabled

On Mon, Jun 15, 2020 at 10:28:07AM +0200, Paulo de Rezende Pinatti wrote: > This patch introduces a common function to verify if the > availability of the so-called Secure Guest feature on the host > has changed in order to invalidate the qemu capabilities cache. > It can be used as an entry point for verification on different > architectures. > > For s390 the verification consists of: > - checking if /sys/firmware/uv is available: meaning the HW > facility is available and the host OS supports it; > - checking if the kernel cmdline contains 'prot_virt=1': meaning > the host OS wants to use the feature. > > Whenever the availability of the feature does not match the secure > guest flag in the cache then libvirt will re-build it in order to > pick up the new set of capabilities available. > > Signed-off-by: Paulo de Rezende Pinatti <ppinatti(a)linux.ibm.com&gt; > Signed-off-by: Boris Fiuczynski <fiuczy(a)linux.ibm.com&gt; > Tested-by: Viktor Mihajlovski <mihajlov(a)linux.ibm.com&gt; > Reviewed-by: Bjoern Walk <bwalk(a)linux.ibm.com&gt; > --- Reviewed-by: Erik Skultety <eskultet(a)redhat.com&gt; I'll squash the following in: diff --git a/src/qemu/qemu_capabilities.c b/src/qemu/qemu_capabilities.c index 0bade7e71b..54835f12a6 100644 --- a/src/qemu/qemu_capabilities.c +++ b/src/qemu/qemu_capabilities.c @@ -4699,12 +4699,8 @@ virQEMUCapsKVMSupportsSecureGuestS390(void) if (!virFileIsDir("/sys/firmware/uv")) return false; - if (virFileReadValueString(&cmdline, "/proc/cmdline") < 0) return false; - - /* we're prefix matching rather than equality matching here, because kernel - * would treat even something like prot_virt='yFOO' as enabled */ if (virKernelCmdlineMatchParam(cmdline, "prot_virt", kValues, G_N_ELEMENTS(kValues), VIR_KERNEL_CMDLINE_FLAGS_SEARCH_FIRST |