Vineeth Pillai <viremana@xxxxxxxxxxxxxxxxxxx> writes:
> From Hyper-V TLFS:
> "The hypervisor exposes hypercalls (HvFlushVirtualAddressSpace,
> HvFlushVirtualAddressSpaceEx, HvFlushVirtualAddressList, and
> HvFlushVirtualAddressListEx) that allow operating systems to more
> efficiently manage the virtual TLB. The L1 hypervisor can choose to
> allow its guest to use those hypercalls and delegate the responsibility
> to handle them to the L0 hypervisor. This requires the use of a
> partition assist page."
>
> Add the Direct Virtual Flush support for SVM.
>
> Related VMX changes:
> commit 6f6a657c9998 ("KVM/Hyper-V/VMX: Add direct tlb flush support")
>
> Signed-off-by: Vineeth Pillai <viremana@xxxxxxxxxxxxxxxxxxx>
> ---
> arch/x86/kvm/Makefile | 4 ++++
> arch/x86/kvm/svm/svm.c | 2 ++
> arch/x86/kvm/svm/svm_onhyperv.c | 41 +++++++++++++++++++++++++++++++++
> arch/x86/kvm/svm/svm_onhyperv.h | 36 +++++++++++++++++++++++++++++
> 4 files changed, 83 insertions(+)
> create mode 100644 arch/x86/kvm/svm/svm_onhyperv.c
>
> diff --git a/arch/x86/kvm/Makefile b/arch/x86/kvm/Makefile
> index a06745c2fef1..83331376b779 100644
> --- a/arch/x86/kvm/Makefile
> +++ b/arch/x86/kvm/Makefile
> @@ -32,6 +32,10 @@ kvm-intel-$(CONFIG_X86_SGX_KVM) += vmx/sgx.o
>
> kvm-amd-y += svm/svm.o svm/vmenter.o svm/pmu.o svm/nested.o svm/avic.o svm/sev.o
>
> +ifdef CONFIG_HYPERV
> +kvm-amd-y += svm/svm_onhyperv.o
> +endif
> +
> obj-$(CONFIG_KVM) += kvm.o
> obj-$(CONFIG_KVM_INTEL) += kvm-intel.o
> obj-$(CONFIG_KVM_AMD) += kvm-amd.o
> diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
> index d2a625411059..5139cb6baadc 100644
> --- a/arch/x86/kvm/svm/svm.c
> +++ b/arch/x86/kvm/svm/svm.c
> @@ -3779,6 +3779,8 @@ static __no_kcsan fastpath_t svm_vcpu_run(struct kvm_vcpu *vcpu)
> }
> svm->vmcb->save.cr2 = vcpu->arch.cr2;
>
> + svm_hv_update_vp_id(svm->vmcb, vcpu);
> +
> /*
> * Run with all-zero DR6 unless needed, so that we can get the exact cause
> * of a #DB.
> diff --git a/arch/x86/kvm/svm/svm_onhyperv.c b/arch/x86/kvm/svm/svm_onhyperv.c
> new file mode 100644
> index 000000000000..3281856ebd94
> --- /dev/null
> +++ b/arch/x86/kvm/svm/svm_onhyperv.c
> @@ -0,0 +1,41 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * KVM L1 hypervisor optimizations on Hyper-V for SVM.
> + */
> +
> +#include <linux/kvm_host.h>
> +#include "kvm_cache_regs.h"
> +
> +#include <asm/mshyperv.h>
> +
> +#include "svm.h"
> +#include "svm_ops.h"
> +
> +#include "hyperv.h"
> +#include "kvm_onhyperv.h"
> +#include "svm_onhyperv.h"
> +
> +int hv_enable_direct_tlbflush(struct kvm_vcpu *vcpu)
> +{
I would've avoided re-using 'hv_enable_direct_tlbflush()' name which we
already have in vmx. In fact, in the spirit of this patch, I'd suggest
we create arch/x86/kvm/vmx/vmx_onhyperv.c and move the existing
hv_enable_direct_tlbflush() there. We can then re-name it to e.g.
vmx_enable_hv_direct_tlbflush()
so the one introduced by this patch will be
svm_enable_hv_direct_tlbflush()
> + struct hv_enlightenments *hve;
> + struct hv_partition_assist_pg **p_hv_pa_pg =
> + &to_kvm_hv(vcpu->kvm)->hv_pa_pg;
> +
> + if (!*p_hv_pa_pg)
> + *p_hv_pa_pg = kzalloc(PAGE_SIZE, GFP_KERNEL);
> +
> + if (!*p_hv_pa_pg)
> + return -ENOMEM;
> +
> + hve = (struct hv_enlightenments *)to_svm(vcpu)->vmcb->control.reserved_sw;
> +
> + hve->partition_assist_page = __pa(*p_hv_pa_pg);
> + hve->hv_vm_id = (unsigned long)vcpu->kvm;
> + if (!hve->hv_enlightenments_control.nested_flush_hypercall) {
> + hve->hv_enlightenments_control.nested_flush_hypercall = 1;
> + vmcb_mark_dirty(to_svm(vcpu)->vmcb, VMCB_HV_NESTED_ENLIGHTENMENTS);
> + }
> +
> + return 0;
> +}
> +
> diff --git a/arch/x86/kvm/svm/svm_onhyperv.h b/arch/x86/kvm/svm/svm_onhyperv.h
> index 0f262460b2e6..7487052fcef8 100644
> --- a/arch/x86/kvm/svm/svm_onhyperv.h
> +++ b/arch/x86/kvm/svm/svm_onhyperv.h
> @@ -36,6 +36,8 @@ struct hv_enlightenments {
> */
> #define VMCB_HV_NESTED_ENLIGHTENMENTS VMCB_SW
>
> +int hv_enable_direct_tlbflush(struct kvm_vcpu *vcpu);
> +
> static inline void svm_hv_init_vmcb(struct vmcb *vmcb)
> {
> struct hv_enlightenments *hve =
> @@ -55,6 +57,23 @@ static inline void svm_hv_hardware_setup(void)
> svm_x86_ops.tlb_remote_flush_with_range =
> hv_remote_flush_tlb_with_range;
> }
> +
> + if (ms_hyperv.nested_features & HV_X64_NESTED_DIRECT_FLUSH) {
> + int cpu;
> +
> + pr_info("kvm: Hyper-V Direct TLB Flush enabled\n");
> + for_each_online_cpu(cpu) {
> + struct hv_vp_assist_page *vp_ap =
> + hv_get_vp_assist_page(cpu);
> +
> + if (!vp_ap)
> + continue;
> +
> + vp_ap->nested_control.features.directhypercall = 1;
> + }
> + svm_x86_ops.enable_direct_tlbflush =
> + hv_enable_direct_tlbflush;
> + }
> }
>
> static inline void svm_hv_vmcb_dirty_nested_enlightenments(
> @@ -74,6 +93,18 @@ static inline void svm_hv_vmcb_dirty_nested_enlightenments(
> hve->hv_enlightenments_control.msr_bitmap)
> vmcb_mark_dirty(vmcb, VMCB_HV_NESTED_ENLIGHTENMENTS);
> }
> +
> +static inline void svm_hv_update_vp_id(struct vmcb *vmcb,
> + struct kvm_vcpu *vcpu)
> +{
> + struct hv_enlightenments *hve =
> + (struct hv_enlightenments *)vmcb->control.reserved_sw;
> +
> + if (hve->hv_vp_id != to_hv_vcpu(vcpu)->vp_index) {
> + hve->hv_vp_id = to_hv_vcpu(vcpu)->vp_index;
> + vmcb_mark_dirty(vmcb, VMCB_HV_NESTED_ENLIGHTENMENTS);
> + }
> +}
> #else
>
> static inline void svm_hv_init_vmcb(struct vmcb *vmcb)
> @@ -88,6 +119,11 @@ static inline void svm_hv_vmcb_dirty_nested_enlightenments(
> struct kvm_vcpu *vcpu)
> {
> }
> +
> +static inline void svm_hv_update_vp_id(struct vmcb *vmcb,
> + struct kvm_vcpu *vcpu)
> +{
> +}
> #endif /* CONFIG_HYPERV */
>
> #endif /* __ARCH_X86_KVM_SVM_ONHYPERV_H__ */
--
Vitaly
