linux-kernel - [PATCH] swiotlb: add a SWIOTLB_ANY flag to lift restricted low memory for encryption

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Message-ID: <20250429165330.2644155-1-jun.miao@intel.com>
Date: Tue, 29 Apr 2025 12:53:30 -0400
From: Jun Miao <jun.miao@...el.com>
To: tglx@...utronix.de,
	mingo@...hat.com,
	bp@...en8.de,
	dave.hansen@...ux.intel.com
Cc: x86@...nel.org,
	linux-kernel@...r.kernel.org,
	jun.miao@...el.com,
	fan.du@...el.com
Subject: [PATCH] swiotlb: add a SWIOTLB_ANY flag to lift restricted low memory for encryption

TDX guest wants to allocate a swiotlb buffer that is not restricted
to low memory for the trusted hypervisor scheme. So that allow to pick
a location everywhere for hypervisors with guest memory encryption in
swiotlb_memblock_alloc() interface by adding a new flag.

Signed-off-by: Jun Miao <jun.miao@...el.com>
---
 arch/x86/kernel/pci-dma.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kernel/pci-dma.c b/arch/x86/kernel/pci-dma.c
index 6267363e0189..73b9320c4a7d 100644
--- a/arch/x86/kernel/pci-dma.c
+++ b/arch/x86/kernel/pci-dma.c
@@ -61,7 +61,7 @@ static void __init pci_swiotlb_detect(void)
 	 */
 	if (cc_platform_has(CC_ATTR_GUEST_MEM_ENCRYPT)) {
 		x86_swiotlb_enable = true;
-		x86_swiotlb_flags |= SWIOTLB_FORCE;
+		x86_swiotlb_flags |= SWIOTLB_ANY | SWIOTLB_FORCE;
 	}
 }
 #else
-- 
2.43.0