2020-09-29 11:55:29

by Wangshaobo (bobo)

Subject: [PATCH -next] x86/kvm: Fix build with CONFIG_SMP disabled

When CONFIG_SMP is disabled, build failed like this:

arch/x86/kernel/kvm.c: In function ‘kvm_alloc_cpumask’:
arch/x86/kernel/kvm.c:823:35: error: ‘kvm_send_ipi_mask_allbutself’
undeclared (first use in this function); did you mean ‘apic_send_IPI_allbutself’?
apic->send_IPI_mask_allbutself = kvm_send_ipi_mask_allbutself;
^~~~~~~~~~~~~~~~~~~~~~~~~~~~
apic_send_IPI_allbutself
arch/x86/kernel/kvm.c:823:35: note: each undeclared identifier
is reported only once for each function it appears in

It is because the declaration of kvm_send_ipi_mask_allbutself() is guarded
by CONFIG_SMP. kvm_send_ipi_mask_allbutself() do not need do anything at
this time.

Signed-off-by: Wang ShaoBo <[email protected]>
---
arch/x86/kernel/kvm.c | 7 +++++++
1 file changed, 7 insertions(+)

diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c
index a44398d2bc44..47d65864e29c 100644
--- a/arch/x86/kernel/kvm.c
+++ b/arch/x86/kernel/kvm.c
@@ -611,6 +611,13 @@ static int kvm_cpu_down_prepare(unsigned int cpu)
local_irq_enable();
return 0;
}
+
+#else /* !CONFIG_SMP */
+
+static void kvm_send_ipi_mask_allbutself(const struct cpumask *mask, int vector)
+{
+}
+
#endif

static void kvm_flush_tlb_others(const struct cpumask *cpumask,
--
2.25.1

2020-09-29 12:35:16

by Paolo Bonzini

Subject: Re: [PATCH -next] x86/kvm: Fix build with CONFIG_SMP disabled

On 29/09/20 13:50, Wang ShaoBo wrote:
> When CONFIG_SMP is disabled, build failed like this:
>
> arch/x86/kernel/kvm.c: In function ‘kvm_alloc_cpumask’:
> arch/x86/kernel/kvm.c:823:35: error: ‘kvm_send_ipi_mask_allbutself’
> undeclared (first use in this function); did you mean ‘apic_send_IPI_allbutself’?
> apic->send_IPI_mask_allbutself = kvm_send_ipi_mask_allbutself;
> ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
> apic_send_IPI_allbutself
> arch/x86/kernel/kvm.c:823:35: note: each undeclared identifier
> is reported only once for each function it appears in
>
> It is because the declaration of kvm_send_ipi_mask_allbutself() is guarded
> by CONFIG_SMP. kvm_send_ipi_mask_allbutself() do not need do anything at
> this time.
>
> Signed-off-by: Wang ShaoBo <[email protected]>
> ---
> arch/x86/kernel/kvm.c | 7 +++++++
> 1 file changed, 7 insertions(+)
>
> diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c
> index a44398d2bc44..47d65864e29c 100644
> --- a/arch/x86/kernel/kvm.c
> +++ b/arch/x86/kernel/kvm.c
> @@ -611,6 +611,13 @@ static int kvm_cpu_down_prepare(unsigned int cpu)
> local_irq_enable();
> return 0;
> }
> +
> +#else /* !CONFIG_SMP */
> +
> +static void kvm_send_ipi_mask_allbutself(const struct cpumask *mask, int vector)
> +{
> +}
> +
> #endif
>
> static void kvm_flush_tlb_others(const struct cpumask *cpumask,
>

Hi,

a patch for this is already on the list, though I haven't committed it yet.

Thanks for the report.

Paolo