From: Adrian Hunter Date: Tue, 19 Aug 2025 15:58:09 +0000 (+0300) Subject: x86/tdx: Eliminate duplicate code in tdx_clear_page() X-Git-Tag: v6.18-rc1~93^2~10 X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=94272b084a745940e076a170d8193ac3427292e6;p=thirdparty%2Fkernel%2Flinux.git x86/tdx: Eliminate duplicate code in tdx_clear_page() tdx_clear_page() and reset_tdx_pages() duplicate the TDX page clearing logic. Rename reset_tdx_pages() to tdx_quirk_reset_paddr() and create tdx_quirk_reset_page() to call tdx_quirk_reset_paddr() and be used in place of tdx_clear_page(). The new name reflects that, in fact, the clearing is necessary only for hardware with a certain quirk. That is dealt with in a subsequent patch but doing the rename here avoids additional churn. Note reset_tdx_pages() is slightly different from tdx_clear_page() because, more appropriately, it uses mb() in place of __mb(). Except when extra debugging is enabled (kcsan at present), mb() just calls __mb(). Signed-off-by: Adrian Hunter Signed-off-by: Dave Hansen Reviewed-by: Kirill A. Shutemov Reviewed-by: Binbin Wu Reviewed-by: Xiaoyao Li Reviewed-by: Rick Edgecombe Acked-by: Kai Huang Acked-by: Sean Christopherson Acked-by: Vishal Annapurve Link: https://lore.kernel.org/all/20250819155811.136099-2-adrian.hunter%40intel.com --- diff --git a/arch/x86/include/asm/tdx.h b/arch/x86/include/asm/tdx.h index 7ddef3a698668..57b46f05ff976 100644 --- a/arch/x86/include/asm/tdx.h +++ b/arch/x86/include/asm/tdx.h @@ -131,6 +131,8 @@ int tdx_guest_keyid_alloc(void); u32 tdx_get_nr_guest_keyids(void); void tdx_guest_keyid_free(unsigned int keyid); +void tdx_quirk_reset_page(struct page *page); + struct tdx_td { /* TD root structure: */ struct page *tdr_page; diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c index 66744f5768c8e..f457b2e578b21 100644 --- a/arch/x86/kvm/vmx/tdx.c +++ b/arch/x86/kvm/vmx/tdx.c @@ -281,25 +281,6 @@ static inline void tdx_disassociate_vp(struct kvm_vcpu *vcpu) vcpu->cpu = -1; } -static void tdx_clear_page(struct page *page) -{ - const void *zero_page = (const void *) page_to_virt(ZERO_PAGE(0)); - void *dest = page_to_virt(page); - unsigned long i; - - /* - * The page could have been poisoned. MOVDIR64B also clears - * the poison bit so the kernel can safely use the page again. - */ - for (i = 0; i < PAGE_SIZE; i += 64) - movdir64b(dest + i, zero_page); - /* - * MOVDIR64B store uses WC buffer. Prevent following memory reads - * from seeing potentially poisoned cache. - */ - __mb(); -} - static void tdx_no_vcpus_enter_start(struct kvm *kvm) { struct kvm_tdx *kvm_tdx = to_kvm_tdx(kvm); @@ -345,7 +326,7 @@ static int tdx_reclaim_page(struct page *page) r = __tdx_reclaim_page(page); if (!r) - tdx_clear_page(page); + tdx_quirk_reset_page(page); return r; } @@ -593,7 +574,7 @@ static void tdx_reclaim_td_control_pages(struct kvm *kvm) pr_tdx_error(TDH_PHYMEM_PAGE_WBINVD, err); return; } - tdx_clear_page(kvm_tdx->td.tdr_page); + tdx_quirk_reset_page(kvm_tdx->td.tdr_page); __free_page(kvm_tdx->td.tdr_page); kvm_tdx->td.tdr_page = NULL; @@ -1714,7 +1695,7 @@ static int tdx_sept_drop_private_spte(struct kvm *kvm, gfn_t gfn, pr_tdx_error(TDH_PHYMEM_PAGE_WBINVD, err); return -EIO; } - tdx_clear_page(page); + tdx_quirk_reset_page(page); tdx_unpin(kvm, page); return 0; } diff --git a/arch/x86/virt/vmx/tdx/tdx.c b/arch/x86/virt/vmx/tdx/tdx.c index c7a9a087ccaf5..fc8d8e444f157 100644 --- a/arch/x86/virt/vmx/tdx/tdx.c +++ b/arch/x86/virt/vmx/tdx/tdx.c @@ -637,7 +637,7 @@ err: * clear these pages. Note this function doesn't flush cache of * these TDX private pages. The caller should make sure of that. */ -static void reset_tdx_pages(unsigned long base, unsigned long size) +static void tdx_quirk_reset_paddr(unsigned long base, unsigned long size) { const void *zero_page = (const void *)page_address(ZERO_PAGE(0)); unsigned long phys, end; @@ -654,9 +654,15 @@ static void reset_tdx_pages(unsigned long base, unsigned long size) mb(); } +void tdx_quirk_reset_page(struct page *page) +{ + tdx_quirk_reset_paddr(page_to_phys(page), PAGE_SIZE); +} +EXPORT_SYMBOL_GPL(tdx_quirk_reset_page); + static void tdmr_reset_pamt(struct tdmr_info *tdmr) { - tdmr_do_pamt_func(tdmr, reset_tdx_pages); + tdmr_do_pamt_func(tdmr, tdx_quirk_reset_paddr); } static void tdmrs_reset_pamt_all(struct tdmr_info_list *tdmr_list)