On 8/29/2025 8:06 AM, Sean Christopherson wrote:
> Drop the return code from kvm_x86_ops.remove_external_spte(), a.k.a.
> tdx_sept_remove_private_spte(), as KVM simply does a KVM_BUG_ON() failure,
> and that KVM_BUG_ON() is redundant since all error paths in TDX also do a
> KVM_BUG_ON().
>
> Opportunistically pass the spte instead of the pfn, as the API is clearly
> about removing an spte.
>
> Suggested-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
> Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Binbin Wu <binbin.wu@linux.intel.com>
> ---
> arch/x86/include/asm/kvm_host.h | 4 ++--
> arch/x86/kvm/mmu/tdp_mmu.c | 8 ++------
> arch/x86/kvm/vmx/tdx.c | 17 ++++++++---------
> 3 files changed, 12 insertions(+), 17 deletions(-)
>
> diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
> index 0d3cc0fc27af..d0a8404a6b8f 100644
> --- a/arch/x86/include/asm/kvm_host.h
> +++ b/arch/x86/include/asm/kvm_host.h
> @@ -1852,8 +1852,8 @@ struct kvm_x86_ops {
> void *external_spt);
>
> /* Update external page table from spte getting removed, and flush TLB. */
> - int (*remove_external_spte)(struct kvm *kvm, gfn_t gfn, enum pg_level level,
> - kvm_pfn_t pfn_for_gfn);
> + void (*remove_external_spte)(struct kvm *kvm, gfn_t gfn, enum pg_level level,
> + u64 spte);
>
> bool (*has_wbinvd_exit)(void);
>
> diff --git a/arch/x86/kvm/mmu/tdp_mmu.c b/arch/x86/kvm/mmu/tdp_mmu.c
> index 3ea2dd64ce72..78ee085f7cbc 100644
> --- a/arch/x86/kvm/mmu/tdp_mmu.c
> +++ b/arch/x86/kvm/mmu/tdp_mmu.c
> @@ -362,9 +362,6 @@ static void tdp_mmu_unlink_sp(struct kvm *kvm, struct kvm_mmu_page *sp)
> static void remove_external_spte(struct kvm *kvm, gfn_t gfn, u64 old_spte,
> int level)
> {
> - kvm_pfn_t old_pfn = spte_to_pfn(old_spte);
> - int ret;
> -
> /*
> * External (TDX) SPTEs are limited to PG_LEVEL_4K, and external
> * PTs are removed in a special order, involving free_external_spt().
> @@ -377,9 +374,8 @@ static void remove_external_spte(struct kvm *kvm, gfn_t gfn, u64 old_spte,
>
> /* Zapping leaf spte is allowed only when write lock is held. */
> lockdep_assert_held_write(&kvm->mmu_lock);
> - /* Because write lock is held, operation should success. */
> - ret = kvm_x86_call(remove_external_spte)(kvm, gfn, level, old_pfn);
> - KVM_BUG_ON(ret, kvm);
> +
> + kvm_x86_call(remove_external_spte)(kvm, gfn, level, old_spte);
> }
>
> /**
> diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c
> index 8cb6a2627eb2..07f9ad1fbfb6 100644
> --- a/arch/x86/kvm/vmx/tdx.c
> +++ b/arch/x86/kvm/vmx/tdx.c
> @@ -1809,12 +1809,12 @@ static int tdx_sept_free_private_spt(struct kvm *kvm, gfn_t gfn,
> return tdx_reclaim_page(virt_to_page(private_spt));
> }
>
> -static int tdx_sept_remove_private_spte(struct kvm *kvm, gfn_t gfn,
> - enum pg_level level, kvm_pfn_t pfn)
> +static void tdx_sept_remove_private_spte(struct kvm *kvm, gfn_t gfn,
> + enum pg_level level, u64 spte)
> {
> + struct page *page = pfn_to_page(spte_to_pfn(spte));
> int tdx_level = pg_level_to_tdx_sept_level(level);
> struct kvm_tdx *kvm_tdx = to_kvm_tdx(kvm);
> - struct page *page = pfn_to_page(pfn);
> gpa_t gpa = gfn_to_gpa(gfn);
> u64 err, entry, level_state;
> int ret;
> @@ -1825,15 +1825,15 @@ static int tdx_sept_remove_private_spte(struct kvm *kvm, gfn_t gfn,
> * there can't be anything populated in the private EPT.
> */
> if (KVM_BUG_ON(!is_hkid_assigned(to_kvm_tdx(kvm)), kvm))
> - return -EIO;
> + return;
>
> /* TODO: handle large pages. */
> if (KVM_BUG_ON(level != PG_LEVEL_4K, kvm))
> - return -EIO;
> + return;
>
> ret = tdx_sept_zap_private_spte(kvm, gfn, level, page);
> if (ret <= 0)
> - return ret;
> + return;
>
> /*
> * TDX requires TLB tracking before dropping private page. Do
> @@ -1862,17 +1862,16 @@ static int tdx_sept_remove_private_spte(struct kvm *kvm, gfn_t gfn,
>
> if (KVM_BUG_ON(err, kvm)) {
> pr_tdx_error_2(TDH_MEM_PAGE_REMOVE, err, entry, level_state);
> - return -EIO;
> + return;
> }
>
> err = tdh_phymem_page_wbinvd_hkid((u16)kvm_tdx->hkid, page);
> if (KVM_BUG_ON(err, kvm)) {
> pr_tdx_error(TDH_PHYMEM_PAGE_WBINVD, err);
> - return -EIO;
> + return;
> }
>
> tdx_clear_page(page);
> - return 0;
> }
>
> void tdx_deliver_interrupt(struct kvm_lapic *apic, int delivery_mode,