On 01/11/2018 16:09, Eial Czerwacki wrote: > Greetings, > > On 11/01/2018 03:45 PM, Juergen Gross wrote: >> On 01/11/2018 14:10, Eial Czerwacki wrote: >>> Greetings, >>> >>> On 11/01/2018 12:39 PM, Shai Fultheim (Shai@xxxxxxxxxxx) wrote: >>>> On 01/11/18 11:37, Thomas Gleixner wrote: >>>> >>>>> VSMP support is built even if CONFIG_X86_VSMP is not set. This leads to a build >>>>> breakage when CONFIG_PCI is disabled as well. >>>>> >>>>> Build VSMP code only when selected. >>>> >>>> This patch disables detect_vsmp_box() on systems without CONFIG_X86_VSMP, due to >>>> the recent 6da63eb241a05b0e676d68975e793c0521387141. This is significant >>>> regression that will affect significant number of deployments. >>>> >>>> We will reply shortly with an updated patch that fix the dependency on pv_irq_ops, >>>> and revert to CONFIG_PARAVIRT, with proper protection for CONFIG_PCI. >>>> >>> >>> here is the proper patch which fixes the issue on hand: >>> From ebff534f8cfa55d7c3ab798c44abe879f3fbe2b8 Mon Sep 17 00:00:00 2001 >>> From: Eial Czerwacki <eial@xxxxxxxxxxx> >>> Date: Thu, 1 Nov 2018 15:08:32 +0200 >>> Subject: [PATCH] x86/build: Build VSMP support only if CONFIG_PCI is >>> selected >>> >>> vsmp dependency of pv_irq_ops removed some years ago, so now let's clean >>> it up from vsmp_64.c. >>> >>> In short, "cap & ctl & (1 << 4)" was always returning 0, as such we can >>> remove all the PARAVIRT/PARAVIRT_XXL code handling that. >>> >>> However, the rest of the code depends on CONFIG_PCI, so fix it accordingly. >>> >>> Signed-off-by: Eial Czerwacki <eial@xxxxxxxxxxx> >>> Acked-by: Shai Fultheim <shai@xxxxxxxxxxx> >>> --- >>> arch/x86/Kconfig | 1 - >>> arch/x86/kernel/vsmp_64.c | 80 >>> +++-------------------------------------------- >>> 2 files changed, 5 insertions(+), 76 deletions(-) >>> >>> diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig >>> index c51c989..4b187ca 100644 >>> --- a/arch/x86/Kconfig >>> +++ b/arch/x86/Kconfig >>> @@ -524,7 +524,6 @@ config X86_VSMP >>> bool "ScaleMP vSMP" >>> select HYPERVISOR_GUEST >>> select PARAVIRT >> >> Do you really still need PARAVIRT and HYPERVISOR_GUEST? >> Maybe you want IRQ_REMAP instead? >> > Better performance is achieved with PARAVIRTed kernel. Hence we keep > them both in. Do you have an explanation for that? Normally PARAVIRT is expected to have a small negative impact on performance. Juergen
