[PATCH 8/8] treewide: Replace the use of mem_encrypt_active() with cc_platform_has()

From: Borislav Petkov
Date: Tue Sep 28 2021 - 15:10:49 EST


From: Tom Lendacky <thomas.lendacky@xxxxxxx>

Replace uses of mem_encrypt_active() with calls to cc_platform_has() with
the CC_ATTR_MEM_ENCRYPT attribute.

Remove the implementation of mem_encrypt_active() across all arches.

For s390, since the default implementation of the cc_platform_has()
matches the s390 implementation of mem_encrypt_active(), cc_platform_has()
does not need to be implemented in s390 (the config option
ARCH_HAS_CC_PLATFORM is not set).

Signed-off-by: Tom Lendacky <thomas.lendacky@xxxxxxx>
Signed-off-by: Borislav Petkov <bp@xxxxxxx>
---
arch/powerpc/include/asm/mem_encrypt.h | 5 -----
arch/powerpc/platforms/pseries/svm.c | 5 +++--
arch/s390/include/asm/mem_encrypt.h | 2 --
arch/x86/include/asm/mem_encrypt.h | 5 -----
arch/x86/kernel/head64.c | 9 +++++++--
arch/x86/mm/ioremap.c | 4 ++--
arch/x86/mm/mem_encrypt.c | 2 +-
arch/x86/mm/pat/set_memory.c | 3 ++-
drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c | 4 +++-
drivers/gpu/drm/drm_cache.c | 4 ++--
drivers/gpu/drm/vmwgfx/vmwgfx_drv.c | 4 ++--
drivers/gpu/drm/vmwgfx/vmwgfx_msg.c | 6 +++---
drivers/iommu/amd/iommu.c | 3 ++-
drivers/iommu/amd/iommu_v2.c | 3 ++-
drivers/iommu/iommu.c | 3 ++-
fs/proc/vmcore.c | 6 +++---
include/linux/mem_encrypt.h | 4 ----
kernel/dma/swiotlb.c | 4 ++--
18 files changed, 36 insertions(+), 40 deletions(-)

diff --git a/arch/powerpc/include/asm/mem_encrypt.h b/arch/powerpc/include/asm/mem_encrypt.h
index ba9dab07c1be..2f26b8fc8d29 100644
--- a/arch/powerpc/include/asm/mem_encrypt.h
+++ b/arch/powerpc/include/asm/mem_encrypt.h
@@ -10,11 +10,6 @@

#include <asm/svm.h>

-static inline bool mem_encrypt_active(void)
-{
- return is_secure_guest();
-}
-
static inline bool force_dma_unencrypted(struct device *dev)
{
return is_secure_guest();
diff --git a/arch/powerpc/platforms/pseries/svm.c b/arch/powerpc/platforms/pseries/svm.c
index 87f001b4c4e4..c083ecbbae4d 100644
--- a/arch/powerpc/platforms/pseries/svm.c
+++ b/arch/powerpc/platforms/pseries/svm.c
@@ -8,6 +8,7 @@

#include <linux/mm.h>
#include <linux/memblock.h>
+#include <linux/cc_platform.h>
#include <asm/machdep.h>
#include <asm/svm.h>
#include <asm/swiotlb.h>
@@ -63,7 +64,7 @@ void __init svm_swiotlb_init(void)

int set_memory_encrypted(unsigned long addr, int numpages)
{
- if (!mem_encrypt_active())
+ if (!cc_platform_has(CC_ATTR_MEM_ENCRYPT))
return 0;

if (!PAGE_ALIGNED(addr))
@@ -76,7 +77,7 @@ int set_memory_encrypted(unsigned long addr, int numpages)

int set_memory_decrypted(unsigned long addr, int numpages)
{
- if (!mem_encrypt_active())
+ if (!cc_platform_has(CC_ATTR_MEM_ENCRYPT))
return 0;

if (!PAGE_ALIGNED(addr))
diff --git a/arch/s390/include/asm/mem_encrypt.h b/arch/s390/include/asm/mem_encrypt.h
index 2542cbf7e2d1..08a8b96606d7 100644
--- a/arch/s390/include/asm/mem_encrypt.h
+++ b/arch/s390/include/asm/mem_encrypt.h
@@ -4,8 +4,6 @@

#ifndef __ASSEMBLY__

-static inline bool mem_encrypt_active(void) { return false; }
-
int set_memory_encrypted(unsigned long addr, int numpages);
int set_memory_decrypted(unsigned long addr, int numpages);

diff --git a/arch/x86/include/asm/mem_encrypt.h b/arch/x86/include/asm/mem_encrypt.h
index da14ede311aa..2d4f5c17d79c 100644
--- a/arch/x86/include/asm/mem_encrypt.h
+++ b/arch/x86/include/asm/mem_encrypt.h
@@ -96,11 +96,6 @@ static inline void mem_encrypt_free_decrypted_mem(void) { }

extern char __start_bss_decrypted[], __end_bss_decrypted[], __start_bss_decrypted_unused[];

-static inline bool mem_encrypt_active(void)
-{
- return sme_me_mask;
-}
-
static inline u64 sme_get_me_mask(void)
{
return sme_me_mask;
diff --git a/arch/x86/kernel/head64.c b/arch/x86/kernel/head64.c
index de01903c3735..fc5371a7e9d1 100644
--- a/arch/x86/kernel/head64.c
+++ b/arch/x86/kernel/head64.c
@@ -19,7 +19,7 @@
#include <linux/start_kernel.h>
#include <linux/io.h>
#include <linux/memblock.h>
-#include <linux/mem_encrypt.h>
+#include <linux/cc_platform.h>
#include <linux/pgtable.h>

#include <asm/processor.h>
@@ -284,8 +284,13 @@ unsigned long __head __startup_64(unsigned long physaddr,
* The bss section will be memset to zero later in the initialization so
* there is no need to zero it after changing the memory encryption
* attribute.
+ *
+ * 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 (mem_encrypt_active()) {
+ if (sme_get_me_mask()) {
vaddr = (unsigned long)__start_bss_decrypted;
vaddr_end = (unsigned long)__end_bss_decrypted;
for (; vaddr < vaddr_end; vaddr += PMD_SIZE) {
diff --git a/arch/x86/mm/ioremap.c b/arch/x86/mm/ioremap.c
index b59a5cbc6bc5..026031b3b782 100644
--- a/arch/x86/mm/ioremap.c
+++ b/arch/x86/mm/ioremap.c
@@ -694,7 +694,7 @@ static bool __init early_memremap_is_setup_data(resource_size_t phys_addr,
bool arch_memremap_can_ram_remap(resource_size_t phys_addr, unsigned long size,
unsigned long flags)
{
- if (!mem_encrypt_active())
+ if (!cc_platform_has(CC_ATTR_MEM_ENCRYPT))
return true;

if (flags & MEMREMAP_ENC)
@@ -724,7 +724,7 @@ pgprot_t __init early_memremap_pgprot_adjust(resource_size_t phys_addr,
{
bool encrypted_prot;

- if (!mem_encrypt_active())
+ if (!cc_platform_has(CC_ATTR_MEM_ENCRYPT))
return prot;

encrypted_prot = true;
diff --git a/arch/x86/mm/mem_encrypt.c b/arch/x86/mm/mem_encrypt.c
index 2d04c39bea1d..23d54b810f08 100644
--- a/arch/x86/mm/mem_encrypt.c
+++ b/arch/x86/mm/mem_encrypt.c
@@ -400,7 +400,7 @@ void __init mem_encrypt_free_decrypted_mem(void)
* The unused memory range was mapped decrypted, change the encryption
* attribute from decrypted to encrypted before freeing it.
*/
- if (mem_encrypt_active()) {
+ if (cc_platform_has(CC_ATTR_MEM_ENCRYPT)) {
r = set_memory_encrypted(vaddr, npages);
if (r) {
pr_warn("failed to free unused decrypted pages\n");
diff --git a/arch/x86/mm/pat/set_memory.c b/arch/x86/mm/pat/set_memory.c
index ad8a5c586a35..527957586f3c 100644
--- a/arch/x86/mm/pat/set_memory.c
+++ b/arch/x86/mm/pat/set_memory.c
@@ -18,6 +18,7 @@
#include <linux/libnvdimm.h>
#include <linux/vmstat.h>
#include <linux/kernel.h>
+#include <linux/cc_platform.h>

#include <asm/e820/api.h>
#include <asm/processor.h>
@@ -1986,7 +1987,7 @@ static int __set_memory_enc_dec(unsigned long addr, int numpages, bool enc)
int ret;

/* Nothing to do if memory encryption is not active */
- if (!mem_encrypt_active())
+ if (!cc_platform_has(CC_ATTR_MEM_ENCRYPT))
return 0;

/* Should not be working on unaligned addresses */
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
index f18240f87387..7741195eb85e 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
@@ -38,6 +38,7 @@
#include <drm/drm_probe_helper.h>
#include <linux/mmu_notifier.h>
#include <linux/suspend.h>
+#include <linux/cc_platform.h>

#include "amdgpu.h"
#include "amdgpu_irq.h"
@@ -1269,7 +1270,8 @@ static int amdgpu_pci_probe(struct pci_dev *pdev,
* however, SME requires an indirect IOMMU mapping because the encryption
* bit is beyond the DMA mask of the chip.
*/
- if (mem_encrypt_active() && ((flags & AMD_ASIC_MASK) == CHIP_RAVEN)) {
+ if (cc_platform_has(CC_ATTR_MEM_ENCRYPT) &&
+ ((flags & AMD_ASIC_MASK) == CHIP_RAVEN)) {
dev_info(&pdev->dev,
"SME is not compatible with RAVEN\n");
return -ENOTSUPP;
diff --git a/drivers/gpu/drm/drm_cache.c b/drivers/gpu/drm/drm_cache.c
index 30cc59fe6ef7..f19d9acbe959 100644
--- a/drivers/gpu/drm/drm_cache.c
+++ b/drivers/gpu/drm/drm_cache.c
@@ -31,7 +31,7 @@
#include <linux/dma-buf-map.h>
#include <linux/export.h>
#include <linux/highmem.h>
-#include <linux/mem_encrypt.h>
+#include <linux/cc_platform.h>
#include <xen/xen.h>

#include <drm/drm_cache.h>
@@ -204,7 +204,7 @@ bool drm_need_swiotlb(int dma_bits)
* Enforce dma_alloc_coherent when memory encryption is active as well
* for the same reasons as for Xen paravirtual hosts.
*/
- if (mem_encrypt_active())
+ if (cc_platform_has(CC_ATTR_MEM_ENCRYPT))
return true;

for (tmp = iomem_resource.child; tmp; tmp = tmp->sibling)
diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_drv.c b/drivers/gpu/drm/vmwgfx/vmwgfx_drv.c
index ab9a1750e1df..bfd71c86faa5 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_drv.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_drv.c
@@ -29,7 +29,7 @@
#include <linux/dma-mapping.h>
#include <linux/module.h>
#include <linux/pci.h>
-#include <linux/mem_encrypt.h>
+#include <linux/cc_platform.h>

#include <drm/drm_aperture.h>
#include <drm/drm_drv.h>
@@ -666,7 +666,7 @@ static int vmw_dma_select_mode(struct vmw_private *dev_priv)
[vmw_dma_map_bind] = "Giving up DMA mappings early."};

/* TTM currently doesn't fully support SEV encryption. */
- if (mem_encrypt_active())
+ if (cc_platform_has(CC_ATTR_MEM_ENCRYPT))
return -EINVAL;

if (vmw_force_coherent)
diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_msg.c b/drivers/gpu/drm/vmwgfx/vmwgfx_msg.c
index e50fb82a3030..2aceac7856e2 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_msg.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_msg.c
@@ -28,7 +28,7 @@
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/slab.h>
-#include <linux/mem_encrypt.h>
+#include <linux/cc_platform.h>

#include <asm/hypervisor.h>
#include <drm/drm_ioctl.h>
@@ -160,7 +160,7 @@ static unsigned long vmw_port_hb_out(struct rpc_channel *channel,
unsigned long msg_len = strlen(msg);

/* HB port can't access encrypted memory. */
- if (hb && !mem_encrypt_active()) {
+ if (hb && !cc_platform_has(CC_ATTR_MEM_ENCRYPT)) {
unsigned long bp = channel->cookie_high;
u32 channel_id = (channel->channel_id << 16);

@@ -216,7 +216,7 @@ static unsigned long vmw_port_hb_in(struct rpc_channel *channel, char *reply,
unsigned long si, di, eax, ebx, ecx, edx;

/* HB port can't access encrypted memory */
- if (hb && !mem_encrypt_active()) {
+ if (hb && !cc_platform_has(CC_ATTR_MEM_ENCRYPT)) {
unsigned long bp = channel->cookie_low;
u32 channel_id = (channel->channel_id << 16);

diff --git a/drivers/iommu/amd/iommu.c b/drivers/iommu/amd/iommu.c
index 1722bb161841..9e5da037d949 100644
--- a/drivers/iommu/amd/iommu.c
+++ b/drivers/iommu/amd/iommu.c
@@ -31,6 +31,7 @@
#include <linux/irqdomain.h>
#include <linux/percpu.h>
#include <linux/io-pgtable.h>
+#include <linux/cc_platform.h>
#include <asm/irq_remapping.h>
#include <asm/io_apic.h>
#include <asm/apic.h>
@@ -2238,7 +2239,7 @@ static int amd_iommu_def_domain_type(struct device *dev)
* active, because some of those devices (AMD GPUs) don't have the
* encryption bit in their DMA-mask and require remapping.
*/
- if (!mem_encrypt_active() && dev_data->iommu_v2)
+ if (!cc_platform_has(CC_ATTR_MEM_ENCRYPT) && dev_data->iommu_v2)
return IOMMU_DOMAIN_IDENTITY;

return 0;
diff --git a/drivers/iommu/amd/iommu_v2.c b/drivers/iommu/amd/iommu_v2.c
index a9e568276c99..13cbeb997cc1 100644
--- a/drivers/iommu/amd/iommu_v2.c
+++ b/drivers/iommu/amd/iommu_v2.c
@@ -17,6 +17,7 @@
#include <linux/wait.h>
#include <linux/pci.h>
#include <linux/gfp.h>
+#include <linux/cc_platform.h>

#include "amd_iommu.h"

@@ -742,7 +743,7 @@ int amd_iommu_init_device(struct pci_dev *pdev, int pasids)
* When memory encryption is active the device is likely not in a
* direct-mapped domain. Forbid using IOMMUv2 functionality for now.
*/
- if (mem_encrypt_active())
+ if (cc_platform_has(CC_ATTR_MEM_ENCRYPT))
return -ENODEV;

if (!amd_iommu_v2_supported())
diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index 3303d707bab4..e80261d17a49 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -25,6 +25,7 @@
#include <linux/property.h>
#include <linux/fsl/mc.h>
#include <linux/module.h>
+#include <linux/cc_platform.h>
#include <trace/events/iommu.h>

static struct kset *iommu_group_kset;
@@ -130,7 +131,7 @@ static int __init iommu_subsys_init(void)
else
iommu_set_default_translated(false);

- if (iommu_default_passthrough() && mem_encrypt_active()) {
+ if (iommu_default_passthrough() && cc_platform_has(CC_ATTR_MEM_ENCRYPT)) {
pr_info("Memory encryption detected - Disabling default IOMMU Passthrough\n");
iommu_set_default_translated(false);
}
diff --git a/fs/proc/vmcore.c b/fs/proc/vmcore.c
index 9a15334da208..cdbbf819d2d6 100644
--- a/fs/proc/vmcore.c
+++ b/fs/proc/vmcore.c
@@ -26,7 +26,7 @@
#include <linux/vmalloc.h>
#include <linux/pagemap.h>
#include <linux/uaccess.h>
-#include <linux/mem_encrypt.h>
+#include <linux/cc_platform.h>
#include <asm/io.h>
#include "internal.h"

@@ -177,7 +177,7 @@ ssize_t __weak elfcorehdr_read(char *buf, size_t count, u64 *ppos)
*/
ssize_t __weak elfcorehdr_read_notes(char *buf, size_t count, u64 *ppos)
{
- return read_from_oldmem(buf, count, ppos, 0, mem_encrypt_active());
+ return read_from_oldmem(buf, count, ppos, 0, cc_platform_has(CC_ATTR_MEM_ENCRYPT));
}

/*
@@ -378,7 +378,7 @@ static ssize_t __read_vmcore(char *buffer, size_t buflen, loff_t *fpos,
buflen);
start = m->paddr + *fpos - m->offset;
tmp = read_from_oldmem(buffer, tsz, &start,
- userbuf, mem_encrypt_active());
+ userbuf, cc_platform_has(CC_ATTR_MEM_ENCRYPT));
if (tmp < 0)
return tmp;
buflen -= tsz;
diff --git a/include/linux/mem_encrypt.h b/include/linux/mem_encrypt.h
index 5c4a18a91f89..ae4526389261 100644
--- a/include/linux/mem_encrypt.h
+++ b/include/linux/mem_encrypt.h
@@ -16,10 +16,6 @@

#include <asm/mem_encrypt.h>

-#else /* !CONFIG_ARCH_HAS_MEM_ENCRYPT */
-
-static inline bool mem_encrypt_active(void) { return false; }
-
#endif /* CONFIG_ARCH_HAS_MEM_ENCRYPT */

#ifdef CONFIG_AMD_MEM_ENCRYPT
diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
index 87c40517e822..c4ca040fdb05 100644
--- a/kernel/dma/swiotlb.c
+++ b/kernel/dma/swiotlb.c
@@ -34,7 +34,7 @@
#include <linux/highmem.h>
#include <linux/gfp.h>
#include <linux/scatterlist.h>
-#include <linux/mem_encrypt.h>
+#include <linux/cc_platform.h>
#include <linux/set_memory.h>
#ifdef CONFIG_DEBUG_FS
#include <linux/debugfs.h>
@@ -552,7 +552,7 @@ phys_addr_t swiotlb_tbl_map_single(struct device *dev, phys_addr_t orig_addr,
if (!mem)
panic("Can not allocate SWIOTLB buffer earlier and can't now provide you with the DMA bounce buffer");

- if (mem_encrypt_active())
+ if (cc_platform_has(CC_ATTR_MEM_ENCRYPT))
pr_warn_once("Memory encryption is active and system is using DMA bounce buffers\n");

if (mapping_size > alloc_size) {
--
2.29.2