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From: Kuppuswamy Sathyanarayanan  <sathyanarayanan.kuppuswamy@linux.intel.com>
To: Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
	Peter Zijlstra <peterz@infradead.org>,
	Andy Lutomirski <luto@kernel.org>,
	Bjorn Helgaas <bhelgaas@google.com>,
	Richard Henderson <rth@twiddle.net>,
	Thomas Bogendoerfer <tsbogend@alpha.franken.de>,
	James E J Bottomley <James.Bottomley@HansenPartnership.com>,
	Helge Deller <deller@gmx.de>,
	"David S . Miller" <davem@davemloft.net>,
	Arnd Bergmann <arnd@arndb.de>, Jonathan Corbet <corbet@lwn.net>,
	"Michael S . Tsirkin" <mst@redhat.com>
Cc: Peter H Anvin <hpa@zytor.com>,
	Dave Hansen <dave.hansen@intel.com>,
	Tony Luck <tony.luck@intel.com>,
	Dan Williams <dan.j.williams@intel.com>,
	Andi Kleen <ak@linux.intel.com>,
	Kirill Shutemov <kirill.shutemov@linux.intel.com>,
	Sean Christopherson <seanjc@google.com>,
	Kuppuswamy Sathyanarayanan <knsathya@kernel.org>,
	x86@kernel.org, linux-kernel@vger.kernel.org,
	linux-pci@vger.kernel.org, linux-alpha@vger.kernel.org,
	linux-mips@vger.kernel.org, linux-parisc@vger.kernel.org,
	sparclinux@vger.kernel.org, linux-arch@vger.kernel.org,
	linux-doc@vger.kernel.org,
	virtualization@lists.linux-foundation.org
Subject: [PATCH v4 14/15] x86/tdx: Implement ioremap_shared for x86
Date: Wed,  4 Aug 2021 17:52:17 -0700	[thread overview]
Message-ID: <20210805005218.2912076-15-sathyanarayanan.kuppuswamy@linux.intel.com> (raw)
In-Reply-To: <20210805005218.2912076-1-sathyanarayanan.kuppuswamy@linux.intel.com>

From: Andi Kleen <ak@linux.intel.com>

Implement ioremap_shared for x86. In TDX most memory is encrypted,
but some memory that is used to communicate with the host must
be declared shared with special page table attributes and a
special hypercall. Previously all ioremaped memory was declared
shared, but this leads to various BIOS tables and other private
state being shared, which is a security risk.

This patch replaces the unconditional ioremap sharing with an explicit
ioremap_shared that enables sharing.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
---
 arch/x86/include/asm/io.h |  3 +++
 arch/x86/mm/ioremap.c     | 41 ++++++++++++++++++++++++++++++---------
 2 files changed, 35 insertions(+), 9 deletions(-)

diff --git a/arch/x86/include/asm/io.h b/arch/x86/include/asm/io.h
index 4c9e06a81ebe..51c2c45456bf 100644
--- a/arch/x86/include/asm/io.h
+++ b/arch/x86/include/asm/io.h
@@ -379,6 +379,9 @@ extern void __iomem *ioremap_wc(resource_size_t offset, unsigned long size);
 extern void __iomem *ioremap_wt(resource_size_t offset, unsigned long size);
 #define ioremap_wt ioremap_wt
 
+extern void __iomem *ioremap_shared(resource_size_t offset, unsigned long size);
+#define ioremap_shared ioremap_shared
+
 extern bool is_early_ioremap_ptep(pte_t *ptep);
 
 #define IO_SPACE_LIMIT 0xffff
diff --git a/arch/x86/mm/ioremap.c b/arch/x86/mm/ioremap.c
index 69a60f240124..74260aaa494b 100644
--- a/arch/x86/mm/ioremap.c
+++ b/arch/x86/mm/ioremap.c
@@ -178,7 +178,8 @@ static void __ioremap_check_mem(resource_size_t addr, unsigned long size,
  */
 static void __iomem *
 __ioremap_caller(resource_size_t phys_addr, unsigned long size,
-		 enum page_cache_mode pcm, void *caller, bool encrypted)
+		 enum page_cache_mode pcm, void *caller, bool encrypted,
+		 bool shared)
 {
 	unsigned long offset, vaddr;
 	resource_size_t last_addr;
@@ -248,7 +249,7 @@ __ioremap_caller(resource_size_t phys_addr, unsigned long size,
 	prot = PAGE_KERNEL_IO;
 	if ((io_desc.flags & IORES_MAP_ENCRYPTED) || encrypted)
 		prot = pgprot_encrypted(prot);
-	else if (prot_guest_has(PATTR_GUEST_SHARED_MAPPING_INIT))
+	else if (shared)
 		prot = pgprot_protected_guest(prot);
 
 	switch (pcm) {
@@ -340,7 +341,8 @@ void __iomem *ioremap(resource_size_t phys_addr, unsigned long size)
 	enum page_cache_mode pcm = _PAGE_CACHE_MODE_UC_MINUS;
 
 	return __ioremap_caller(phys_addr, size, pcm,
-				__builtin_return_address(0), false);
+				__builtin_return_address(0), false,
+				false);
 }
 EXPORT_SYMBOL(ioremap);
 
@@ -373,7 +375,8 @@ void __iomem *ioremap_uc(resource_size_t phys_addr, unsigned long size)
 	enum page_cache_mode pcm = _PAGE_CACHE_MODE_UC;
 
 	return __ioremap_caller(phys_addr, size, pcm,
-				__builtin_return_address(0), false);
+				__builtin_return_address(0), false,
+				false);
 }
 EXPORT_SYMBOL_GPL(ioremap_uc);
 
@@ -390,10 +393,29 @@ EXPORT_SYMBOL_GPL(ioremap_uc);
 void __iomem *ioremap_wc(resource_size_t phys_addr, unsigned long size)
 {
 	return __ioremap_caller(phys_addr, size, _PAGE_CACHE_MODE_WC,
-					__builtin_return_address(0), false);
+					__builtin_return_address(0), false,
+					false);
 }
 EXPORT_SYMBOL(ioremap_wc);
 
+/**
+ * ioremap_shared - map memory into CPU space shared with host
+ * @phys_addr:	bus address of the memory
+ * @size:	size of the resource to map
+ *
+ * This version of ioremap ensures that the memory is marked shared
+ * with the host. This is useful for confidential guests.
+ *
+ * Must be freed with iounmap.
+ */
+void __iomem *ioremap_shared(resource_size_t phys_addr, unsigned long size)
+{
+	return __ioremap_caller(phys_addr, size, _PAGE_CACHE_MODE_WC,
+			__builtin_return_address(0), false,
+			prot_guest_has(PATTR_GUEST_SHARED_MAPPING_INIT));
+}
+EXPORT_SYMBOL(ioremap_shared);
+
 /**
  * ioremap_wt	-	map memory into CPU space write through
  * @phys_addr:	bus address of the memory
@@ -407,21 +429,22 @@ EXPORT_SYMBOL(ioremap_wc);
 void __iomem *ioremap_wt(resource_size_t phys_addr, unsigned long size)
 {
 	return __ioremap_caller(phys_addr, size, _PAGE_CACHE_MODE_WT,
-					__builtin_return_address(0), false);
+					__builtin_return_address(0), false,
+					false);
 }
 EXPORT_SYMBOL(ioremap_wt);
 
 void __iomem *ioremap_encrypted(resource_size_t phys_addr, unsigned long size)
 {
 	return __ioremap_caller(phys_addr, size, _PAGE_CACHE_MODE_WB,
-				__builtin_return_address(0), true);
+				__builtin_return_address(0), true, false);
 }
 EXPORT_SYMBOL(ioremap_encrypted);
 
 void __iomem *ioremap_cache(resource_size_t phys_addr, unsigned long size)
 {
 	return __ioremap_caller(phys_addr, size, _PAGE_CACHE_MODE_WB,
-				__builtin_return_address(0), false);
+				__builtin_return_address(0), false, false);
 }
 EXPORT_SYMBOL(ioremap_cache);
 
@@ -430,7 +453,7 @@ void __iomem *ioremap_prot(resource_size_t phys_addr, unsigned long size,
 {
 	return __ioremap_caller(phys_addr, size,
 				pgprot2cachemode(__pgprot(prot_val)),
-				__builtin_return_address(0), false);
+				__builtin_return_address(0), false, false);
 }
 EXPORT_SYMBOL(ioremap_prot);
 
-- 
2.25.1


  parent reply	other threads:[~2021-08-05  0:54 UTC|newest]

Thread overview: 55+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-05  0:52 [PATCH v4 00/15] Add TDX Guest Support (shared-mm support) Kuppuswamy Sathyanarayanan
2021-08-05  0:52 ` [PATCH v4 01/15] x86/mm: Move force_dma_unencrypted() to common code Kuppuswamy Sathyanarayanan
2021-08-05  0:52 ` [PATCH v4 02/15] x86/tdx: Exclude Shared bit from physical_mask Kuppuswamy Sathyanarayanan
2021-08-05  0:52 ` [PATCH v4 03/15] x86/tdx: Make pages shared in ioremap() Kuppuswamy Sathyanarayanan
2021-08-05  0:52 ` [PATCH v4 04/15] x86/tdx: Add helper to do MapGPA hypercall Kuppuswamy Sathyanarayanan
2021-08-05  0:52 ` [PATCH v4 05/15] x86/tdx: Make DMA pages shared Kuppuswamy Sathyanarayanan
2021-08-05  0:52 ` [PATCH v4 06/15] x86/kvm: Use bounce buffers for TD guest Kuppuswamy Sathyanarayanan
2021-08-05  0:52 ` [PATCH v4 07/15] x86/tdx: ioapic: Add shared bit for IOAPIC base address Kuppuswamy Sathyanarayanan
2021-08-05  0:52 ` [PATCH v4 08/15] x86/tdx: Enable shared memory protected guest flags for TDX guest Kuppuswamy Sathyanarayanan
2021-08-05  0:52 ` [PATCH v4 09/15] pci: Consolidate pci_iomap* and pci_iomap*wc Kuppuswamy Sathyanarayanan
2021-08-12 19:43   ` Bjorn Helgaas
2021-08-12 22:11     ` Andi Kleen
2021-08-12 22:29     ` Kuppuswamy, Sathyanarayanan
2021-08-05  0:52 ` [PATCH v4 10/15] asm/io.h: Add ioremap_shared fallback Kuppuswamy Sathyanarayanan
2021-08-12 19:46   ` Bjorn Helgaas
2021-08-13  7:58   ` Christoph Hellwig
2021-08-05  0:52 ` [PATCH v4 11/15] pci: Add pci_iomap_shared{,_range} Kuppuswamy Sathyanarayanan
2021-08-13  8:02   ` Christoph Hellwig
2021-08-23 23:56   ` Michael S. Tsirkin
2021-08-24  0:30     ` Kuppuswamy, Sathyanarayanan
2021-08-24  1:04       ` Dan Williams
2021-08-24  2:14         ` Andi Kleen
2021-08-24  9:47           ` Michael S. Tsirkin
2021-08-24 17:20             ` Andi Kleen
2021-08-24 18:55               ` Bjorn Helgaas
2021-08-24 20:14                 ` Andi Kleen
2021-08-24 20:31                   ` Bjorn Helgaas
2021-08-24 20:50                     ` Andi Kleen
2021-08-24 21:05                       ` Dan Williams
2021-08-25 14:52                       ` Bjorn Helgaas
2021-08-24 21:55                 ` Rajat Jain
2021-08-29 15:27               ` Michael S. Tsirkin
2021-08-29 16:17                 ` Andi Kleen
2021-08-29 22:26                   ` Michael S. Tsirkin
2021-08-30  5:11                     ` Andi Kleen
2021-08-30 20:59                       ` Michael S. Tsirkin
2021-08-31  0:23                         ` Andi Kleen
2021-09-10  9:54                           ` Michael S. Tsirkin
2021-09-10 16:34                             ` Andi Kleen
2021-09-11 23:54                               ` Michael S. Tsirkin
2021-09-13  5:53                                 ` Michael S. Tsirkin
2021-09-24 22:43                                 ` Andi Kleen
2021-09-27  9:07                                   ` Michael S. Tsirkin
2021-08-24 21:56         ` Rajat Jain
2021-08-24 21:59           ` Dan Williams
2021-08-24  7:07       ` Christoph Hellwig
2021-08-24 17:04         ` Andi Kleen
2021-08-29 15:34           ` Michael S. Tsirkin
2021-08-29 16:43             ` Andi Kleen
2021-08-24  9:12       ` Michael S. Tsirkin
2021-08-05  0:52 ` [PATCH v4 12/15] pci: Mark MSI data shared Kuppuswamy Sathyanarayanan
2021-08-13  8:07   ` Christoph Hellwig
2021-08-05  0:52 ` [PATCH v4 13/15] virtio: Use shared mappings for virtio PCI devices Kuppuswamy Sathyanarayanan
2021-08-05  0:52 ` Kuppuswamy Sathyanarayanan [this message]
2021-08-05  0:52 ` [PATCH v4 15/15] x86/tdx: Add cmdline option to force use of ioremap_shared Kuppuswamy Sathyanarayanan

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