linux-kernel - [PATCH 6/7] fixup! KVM: TDX: Implement hooks to propagate changes of TDP MMU mirror page table

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Message-ID: <20250113021312.18976-1-yan.y.zhao@intel.com>
Date: Mon, 13 Jan 2025 10:13:12 +0800
From: Yan Zhao <yan.y.zhao@...el.com>
To: pbonzini@...hat.com,
	seanjc@...gle.com,
	kvm@...r.kernel.org
Cc: linux-kernel@...r.kernel.org,
	rick.p.edgecombe@...el.com,
	kai.huang@...el.com,
	adrian.hunter@...el.com,
	reinette.chatre@...el.com,
	xiaoyao.li@...el.com,
	tony.lindgren@...el.com,
	binbin.wu@...ux.intel.com,
	dmatlack@...gle.com,
	isaku.yamahata@...el.com,
	isaku.yamahata@...il.com
Subject: [PATCH 6/7] fixup! KVM: TDX: Implement hooks to propagate changes of TDP MMU mirror page table

Remove the retry loop for tdh_phymem_page_wbinvd_hkid().

tdh_phymem_page_wbinvd_hkid() just acquires the lock on the PAMT entry of
the page to be wbinvd, so it's not expected to encounter TDX_OPERAND_BUSY.

Signed-off-by: Yan Zhao <yan.y.zhao@...el.com>
---
 arch/x86/kvm/vmx/tdx.c | 9 +--------
 1 file changed, 1 insertion(+), 8 deletions(-)

diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c
index 4fb9faca5db2..baabae95504b 100644
--- a/arch/x86/kvm/vmx/tdx.c
+++ b/arch/x86/kvm/vmx/tdx.c
@@ -1712,14 +1712,7 @@ static int tdx_sept_drop_private_spte(struct kvm *kvm, gfn_t gfn,
 		return -EIO;
 	}
 
-	do {
-		/*
-		 * TDX_OPERAND_BUSY can happen on locking PAMT entry.  Because
-		 * this page was removed above, other thread shouldn't be
-		 * repeatedly operating on this page.  Just retry loop.
-		 */
-		err = tdh_phymem_page_wbinvd_hkid(hpa, (u16)kvm_tdx->hkid);
-	} while (unlikely(err == (TDX_OPERAND_BUSY | TDX_OPERAND_ID_RCX)));
+	err = tdh_phymem_page_wbinvd_hkid(hpa, (u16)kvm_tdx->hkid);
 
 	if (KVM_BUG_ON(err, kvm)) {
 		pr_tdx_error(TDH_PHYMEM_PAGE_WBINVD, err);
-- 
2.43.2