[PATCH 5/8] x86/sme: Replace occurrences of sme_active() with cc_platform_has()

Borislav Petkov
2021-09-28T19:10:53Z

From: Tom Lendacky <thomas.lendacky@amd.com>

Replace uses of sme_active() with the more generic cc_platform_has()
using CC_ATTR_HOST_MEM_ENCRYPT. If future support is added for other
memory encryption technologies, the use of CC_ATTR_HOST_MEM_ENCRYPT
can be updated, as required.

This also replaces two usages of sev_active() that are really geared
towards detecting if SME is active.

Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
---
arch/x86/include/asm/kexec.h | 2 +-
arch/x86/include/asm/mem_encrypt.h | 2 --
arch/x86/kernel/machine_kexec_64.c | 15 ++++++++-------
arch/x86/kernel/pci-swiotlb.c | 9 ++++-----
arch/x86/kernel/relocate_kernel_64.S | 2 +-
arch/x86/mm/ioremap.c | 6 +++---
arch/x86/mm/mem_encrypt.c | 13 ++++---------
arch/x86/mm/mem_encrypt_identity.c | 9 ++++++++-
arch/x86/realmode/init.c | 5 +++--
drivers/iommu/amd/init.c | 7 ++++---
10 files changed, 36 insertions(+), 34 deletions(-)

diff --git a/arch/x86/include/asm/kexec.h b/arch/x86/include/asm/kexec.h
index 0a6e34b07017..11b7c06e2828 100644
--- a/arch/x86/include/asm/kexec.h
+++ b/arch/x86/include/asm/kexec.h
@@ -129,7 +129,7 @@ relocate_kernel(unsigned long indirection_page,
unsigned long page_list,
unsigned long start_address,
unsigned int preserve_context,
- unsigned int sme_active);
+ unsigned int host_mem_enc_active);
#endif

#define ARCH_HAS_KIMAGE_ARCH
diff --git a/arch/x86/include/asm/mem_encrypt.h b/arch/x86/include/asm/mem_encrypt.h
index 3fb9f5ebefa4..63c5b99ccae5 100644
--- a/arch/x86/include/asm/mem_encrypt.h
+++ b/arch/x86/include/asm/mem_encrypt.h
@@ -51,7 +51,6 @@ void __init mem_encrypt_free_decrypted_mem(void);
void __init mem_encrypt_init(void);

void __init sev_es_init_vc_handling(void);
-bool sme_active(void);
bool sev_active(void);
bool sev_es_active(void);

@@ -76,7 +75,6 @@ static inline void __init sme_encrypt_kernel(struct boot_params *bp) { }
static inline void __init sme_enable(struct boot_params *bp) { }

static inline void sev_es_init_vc_handling(void) { }
-static inline bool sme_active(void) { return false; }
static inline bool sev_active(void) { return false; }
static inline bool sev_es_active(void) { return false; }

diff --git a/arch/x86/kernel/machine_kexec_64.c b/arch/x86/kernel/machine_kexec_64.c
index 131f30fdcfbd..7040c0fa921c 100644
--- a/arch/x86/kernel/machine_kexec_64.c
+++ b/arch/x86/kernel/machine_kexec_64.c
@@ -17,6 +17,7 @@
#include <linux/suspend.h>
#include <linux/vmalloc.h>
#include <linux/efi.h>
+#include <linux/cc_platform.h>

#include <asm/init.h>
#include <asm/tlbflush.h>
@@ -358,7 +359,7 @@ void machine_kexec(struct kimage *image)
(unsigned long)page_list,
image->start,
image->preserve_context,
- sme_active());
+ cc_platform_has(CC_ATTR_HOST_MEM_ENCRYPT));

#ifdef CONFIG_KEXEC_JUMP
if (image->preserve_context)
@@ -569,12 +570,12 @@ void arch_kexec_unprotect_crashkres(void)
*/
int arch_kexec_post_alloc_pages(void *vaddr, unsigned int pages, gfp_t gfp)
{
- if (sev_active())
+ if (!cc_platform_has(CC_ATTR_HOST_MEM_ENCRYPT))
return 0;

/*
- * If SME is active we need to be sure that kexec pages are
- * not encrypted because when we boot to the new kernel the
+ * If host memory encryption is active we need to be sure that kexec
+ * pages are not encrypted because when we boot to the new kernel the
* pages won't be accessed encrypted (initially).
*/
return set_memory_decrypted((unsigned long)vaddr, pages);
@@ -582,12 +583,12 @@ int arch_kexec_post_alloc_pages(void *vaddr, unsigned int pages, gfp_t gfp)

void arch_kexec_pre_free_pages(void *vaddr, unsigned int pages)
{
- if (sev_active())
+ if (!cc_platform_has(CC_ATTR_HOST_MEM_ENCRYPT))
return;

/*
- * If SME is active we need to reset the pages back to being
- * an encrypted mapping before freeing them.
+ * If host memory encryption is active we need to reset the pages back
+ * to being an encrypted mapping before freeing them.
*/
set_memory_encrypted((unsigned long)vaddr, pages);
}
diff --git a/arch/x86/kernel/pci-swiotlb.c b/arch/x86/kernel/pci-swiotlb.c
index c2cfa5e7c152..814ab46a0dad 100644
--- a/arch/x86/kernel/pci-swiotlb.c
+++ b/arch/x86/kernel/pci-swiotlb.c
@@ -6,7 +6,7 @@
#include <linux/swiotlb.h>
#include <linux/memblock.h>
#include <linux/dma-direct.h>
-#include <linux/mem_encrypt.h>
+#include <linux/cc_platform.h>

#include <asm/iommu.h>
#include <asm/swiotlb.h>
@@ -45,11 +45,10 @@ int __init pci_swiotlb_detect_4gb(void)
swiotlb = 1;

/*
- * If SME is active then swiotlb will be set to 1 so that bounce
- * buffers are allocated and used for devices that do not support
- * the addressing range required for the encryption mask.
+ * Set swiotlb to 1 so that bounce buffers are allocated and used for
+ * devices that can't support DMA to encrypted memory.
*/
- if (sme_active())
+ if (cc_platform_has(CC_ATTR_HOST_MEM_ENCRYPT))
swiotlb = 1;

return swiotlb;
diff --git a/arch/x86/kernel/relocate_kernel_64.S b/arch/x86/kernel/relocate_kernel_64.S
index c53271aebb64..c8fe74a28143 100644
--- a/arch/x86/kernel/relocate_kernel_64.S
+++ b/arch/x86/kernel/relocate_kernel_64.S
@@ -47,7 +47,7 @@ SYM_CODE_START_NOALIGN(relocate_kernel)
* %rsi page_list
* %rdx start address
* %rcx preserve_context
- * %r8 sme_active
+ * %r8 host_mem_enc_active
*/

/* Save the CPU context, used for jumping back */
diff --git a/arch/x86/mm/ioremap.c b/arch/x86/mm/ioremap.c
index ccff76cedd8f..a7250fa3d45f 100644
--- a/arch/x86/mm/ioremap.c
+++ b/arch/x86/mm/ioremap.c
@@ -14,7 +14,7 @@
#include <linux/slab.h>
#include <linux/vmalloc.h>
#include <linux/mmiotrace.h>
-#include <linux/mem_encrypt.h>
+#include <linux/cc_platform.h>
#include <linux/efi.h>
#include <linux/pgtable.h>

@@ -703,7 +703,7 @@ bool arch_memremap_can_ram_remap(resource_size_t phys_addr, unsigned long size,
if (flags & MEMREMAP_DEC)
return false;

- if (sme_active()) {
+ if (cc_platform_has(CC_ATTR_HOST_MEM_ENCRYPT)) {
if (memremap_is_setup_data(phys_addr, size) ||
memremap_is_efi_data(phys_addr, size))
return false;
@@ -729,7 +729,7 @@ pgprot_t __init early_memremap_pgprot_adjust(resource_size_t phys_addr,

encrypted_prot = true;

- if (sme_active()) {
+ if (cc_platform_has(CC_ATTR_HOST_MEM_ENCRYPT)) {
if (early_memremap_is_setup_data(phys_addr, size) ||
memremap_is_efi_data(phys_addr, size))
encrypted_prot = false;
diff --git a/arch/x86/mm/mem_encrypt.c b/arch/x86/mm/mem_encrypt.c
index e29b1418d00c..2163485a74e1 100644
--- a/arch/x86/mm/mem_encrypt.c
+++ b/arch/x86/mm/mem_encrypt.c
@@ -144,7 +144,7 @@ void __init sme_unmap_bootdata(char *real_mode_data)
struct boot_params *boot_data;
unsigned long cmdline_paddr;

- if (!sme_active())
+ if (!cc_platform_has(CC_ATTR_HOST_MEM_ENCRYPT))
return;

/* Get the command line address before unmapping the real_mode_data */
@@ -164,7 +164,7 @@ void __init sme_map_bootdata(char *real_mode_data)
struct boot_params *boot_data;
unsigned long cmdline_paddr;

- if (!sme_active())
+ if (!cc_platform_has(CC_ATTR_HOST_MEM_ENCRYPT))
return;

__sme_early_map_unmap_mem(real_mode_data, sizeof(boot_params), true);
@@ -377,11 +377,6 @@ bool sev_active(void)
{
return sev_status & MSR_AMD64_SEV_ENABLED;
}
-
-bool sme_active(void)
-{
- return sme_me_mask && !sev_active();
-}
EXPORT_SYMBOL_GPL(sev_active);

/* Needs to be called from non-instrumentable code */
@@ -404,7 +399,7 @@ bool force_dma_unencrypted(struct device *dev)
* device does not support DMA to addresses that include the
* encryption mask.
*/
- if (sme_active()) {
+ if (cc_platform_has(CC_ATTR_HOST_MEM_ENCRYPT)) {
u64 dma_enc_mask = DMA_BIT_MASK(__ffs64(sme_me_mask));
u64 dma_dev_mask = min_not_zero(dev->coherent_dma_mask,
dev->bus_dma_limit);
@@ -445,7 +440,7 @@ static void print_mem_encrypt_feature_info(void)
pr_info("AMD Memory Encryption Features active:");

/* Secure Memory Encryption */
- if (sme_active()) {
+ if (cc_platform_has(CC_ATTR_HOST_MEM_ENCRYPT)) {
/*
* SME is mutually exclusive with any of the SEV
* features below.
diff --git a/arch/x86/mm/mem_encrypt_identity.c b/arch/x86/mm/mem_encrypt_identity.c
index 470b20208430..f8c612902038 100644
--- a/arch/x86/mm/mem_encrypt_identity.c
+++ b/arch/x86/mm/mem_encrypt_identity.c
@@ -30,6 +30,7 @@
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/mem_encrypt.h>
+#include <linux/cc_platform.h>

#include <asm/setup.h>
#include <asm/sections.h>
@@ -287,7 +288,13 @@ void __init sme_encrypt_kernel(struct boot_params *bp)
unsigned long pgtable_area_len;
unsigned long decrypted_base;

- if (!sme_active())
+ /*
+ * This is early code, use an open coded check for SME instead of
+ * using cc_platform_has(). This eliminates worries about removing
+ * instrumentation or checking boot_cpu_data in the cc_platform_has()
+ * function.
+ */
+ if (!sme_get_me_mask() || sev_status & MSR_AMD64_SEV_ENABLED)
return;

/*
diff --git a/arch/x86/realmode/init.c b/arch/x86/realmode/init.c
index 31b5856010cb..c878c5ee5a4c 100644
--- a/arch/x86/realmode/init.c
+++ b/arch/x86/realmode/init.c
@@ -3,6 +3,7 @@
#include <linux/slab.h>
#include <linux/memblock.h>
#include <linux/mem_encrypt.h>
+#include <linux/cc_platform.h>
#include <linux/pgtable.h>

#include <asm/set_memory.h>
@@ -44,7 +45,7 @@ void __init reserve_real_mode(void)
static void sme_sev_setup_real_mode(struct trampoline_header *th)
{
#ifdef CONFIG_AMD_MEM_ENCRYPT
- if (sme_active())
+ if (cc_platform_has(CC_ATTR_HOST_MEM_ENCRYPT))
th->flags |= TH_FLAGS_SME_ACTIVE;

if (sev_es_active()) {
@@ -81,7 +82,7 @@ static void __init setup_real_mode(void)
* decrypted memory in order to bring up other processors
* successfully. This is not needed for SEV.
*/
- if (sme_active())
+ if (cc_platform_has(CC_ATTR_HOST_MEM_ENCRYPT))
set_memory_decrypted((unsigned long)base, size >> PAGE_SHIFT);

memcpy(base, real_mode_blob, size);
diff --git a/drivers/iommu/amd/init.c b/drivers/iommu/amd/init.c
index 2a822b229bd0..c6c53e18dace 100644
--- a/drivers/iommu/amd/init.c
+++ b/drivers/iommu/amd/init.c
@@ -20,7 +20,7 @@
#include <linux/amd-iommu.h>
#include <linux/export.h>
#include <linux/kmemleak.h>
-#include <linux/mem_encrypt.h>
+#include <linux/cc_platform.h>
#include <asm/pci-direct.h>
#include <asm/iommu.h>
#include <asm/apic.h>
@@ -964,7 +964,7 @@ static bool copy_device_table(void)
pr_err("The address of old device table is above 4G, not trustworthy!\n");
return false;
}
- old_devtb = (sme_active() && is_kdump_kernel())
+ old_devtb = (cc_platform_has(CC_ATTR_HOST_MEM_ENCRYPT) && is_kdump_kernel())
? (__force void *)ioremap_encrypted(old_devtb_phys,
dev_table_size)
: memremap(old_devtb_phys, dev_table_size, MEMREMAP_WB);
@@ -3032,7 +3032,8 @@ static int __init amd_iommu_init(void)

static bool amd_iommu_sme_check(void)
{
- if (!sme_active() || (boot_cpu_data.x86 != 0x17))
+ if (!cc_platform_has(CC_ATTR_HOST_MEM_ENCRYPT) ||
+ (boot_cpu_data.x86 != 0x17))
return true;

/* For Fam17h, a specific level of support is required */
--
2.29.2