KVM: x86: Introduce new ioctl KVM_HYPERV_SET_TLB_FLUSH_INHIBIT

[PATCH 4/7] KVM: Introduce KVM_HYPERV_SET_TLB_FLUSH_INHIBIT

Posted by Nikolas Wipper 1 month, 3 weeks ago

Introduce a new ioctl to control whether remote flushing via Hyper-V
hyper-calls should be allowed on a vCPU. When the tlb_flush_inhibit bit is
set, vCPUs attempting to flush the TLB of the inhibitied vCPU will be
suspended until the bit is clearded.

Signed-off-by: Nikolas Wipper <nikwip@amazon.de>
---
 include/uapi/linux/kvm.h | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
index 637efc055145..3bc43fdcab88 100644
--- a/include/uapi/linux/kvm.h
+++ b/include/uapi/linux/kvm.h
@@ -933,6 +933,7 @@ struct kvm_enable_cap {
 #define KVM_CAP_PRE_FAULT_MEMORY 236
 #define KVM_CAP_X86_APIC_BUS_CYCLES_NS 237
 #define KVM_CAP_X86_GUEST_MODE 238
+#define KVM_CAP_HYPERV_TLB_FLUSH_INHIBIT 239
 
 struct kvm_irq_routing_irqchip {
 	__u32 irqchip;
@@ -1573,4 +1574,18 @@ struct kvm_pre_fault_memory {
 	__u64 padding[5];
 };
 
+/* Available with KVM_CAP_HYPERV_TLBFLUSH */
+#define KVM_HYPERV_SET_TLB_FLUSH_INHIBIT \
+	_IOW(KVMIO,  0xd6, struct kvm_hyperv_tlb_flush_inhibit)
+
+/* for KVM_HYPERV_SET_TLB_FLUSH_INHIBIT */
+struct kvm_hyperv_tlb_flush_inhibit {
+	/* in */
+	__u16 flags;
+#define KVM_HYPERV_UNINHIBIT_TLB_FLUSH 0
+#define KVM_HYPERV_INHIBIT_TLB_FLUSH 1
+	__u8  inhibit;
+	__u8  reserved[5];
+};
+
 #endif /* __LINUX_KVM_H */
-- 
2.40.1




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Geschaeftsfuehrung: Christian Schlaeger, Jonathan Weiss
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Re: [PATCH 4/7] KVM: Introduce KVM_HYPERV_SET_TLB_FLUSH_INHIBIT

Posted by Vitaly Kuznetsov 1 month, 2 weeks ago

Nikolas Wipper <nikwip@amazon.de> writes:

> Introduce a new ioctl to control whether remote flushing via Hyper-V
> hyper-calls should be allowed on a vCPU. When the tlb_flush_inhibit bit is
> set, vCPUs attempting to flush the TLB of the inhibitied vCPU will be
> suspended until the bit is clearded.
>
> Signed-off-by: Nikolas Wipper <nikwip@amazon.de>
> ---
>  include/uapi/linux/kvm.h | 15 +++++++++++++++

I guess we can merge this patch with documentation (PATCH1) or even
implementation (PATCH5) as I don't see why separation helps here.

>  1 file changed, 15 insertions(+)
>
> diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
> index 637efc055145..3bc43fdcab88 100644
> --- a/include/uapi/linux/kvm.h
> +++ b/include/uapi/linux/kvm.h
> @@ -933,6 +933,7 @@ struct kvm_enable_cap {
>  #define KVM_CAP_PRE_FAULT_MEMORY 236
>  #define KVM_CAP_X86_APIC_BUS_CYCLES_NS 237
>  #define KVM_CAP_X86_GUEST_MODE 238
> +#define KVM_CAP_HYPERV_TLB_FLUSH_INHIBIT 239
>  
>  struct kvm_irq_routing_irqchip {
>  	__u32 irqchip;
> @@ -1573,4 +1574,18 @@ struct kvm_pre_fault_memory {
>  	__u64 padding[5];
>  };
>  
> +/* Available with KVM_CAP_HYPERV_TLBFLUSH */
> +#define KVM_HYPERV_SET_TLB_FLUSH_INHIBIT \
> +	_IOW(KVMIO,  0xd6, struct kvm_hyperv_tlb_flush_inhibit)
> +
> +/* for KVM_HYPERV_SET_TLB_FLUSH_INHIBIT */
> +struct kvm_hyperv_tlb_flush_inhibit {
> +	/* in */
> +	__u16 flags;
> +#define KVM_HYPERV_UNINHIBIT_TLB_FLUSH 0
> +#define KVM_HYPERV_INHIBIT_TLB_FLUSH 1
> +	__u8  inhibit;
> +	__u8  reserved[5];
> +};
> +
>  #endif /* __LINUX_KVM_H */

-- 
Vitaly