[PATCH v2 06/12] x86/sev: Replace occurrences of sev_active() with prot_guest_has()

Tom Lendacky
2021-08-13T17:00:44Z

Replace occurrences of sev_active() with the more generic prot_guest_has()
using PATTR_GUEST_MEM_ENCRYPT, except for in arch/x86/mm/mem_encrypt*.c
where PATTR_SEV will be used. If future support is added for other memory
encryption technologies, the use of PATTR_GUEST_MEM_ENCRYPT can be
updated, as required, to use PATTR_SEV.

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
---
arch/x86/include/asm/mem_encrypt.h | 2 --
arch/x86/kernel/crash_dump_64.c | 4 +++-
arch/x86/kernel/kvm.c | 3 ++-
arch/x86/kernel/kvmclock.c | 4 ++--
arch/x86/kernel/machine_kexec_64.c | 16 ++++++++--------
arch/x86/kvm/svm/svm.c | 3 ++-
arch/x86/mm/ioremap.c | 6 +++---
arch/x86/mm/mem_encrypt.c | 15 +++++++--------
arch/x86/platform/efi/efi_64.c | 9 +++++----
9 files changed, 32 insertions(+), 30 deletions(-)

diff --git a/arch/x86/include/asm/mem_encrypt.h b/arch/x86/include/asm/mem_encrypt.h
index 956338406cec..7e25de37c148 100644
--- a/arch/x86/include/asm/mem_encrypt.h
+++ b/arch/x86/include/asm/mem_encrypt.h
@@ -50,7 +50,6 @@ void __init mem_encrypt_free_decrypted_mem(void);
void __init mem_encrypt_init(void);

void __init sev_es_init_vc_handling(void);
-bool sev_active(void);
bool sev_es_active(void);
bool amd_prot_guest_has(unsigned int attr);

@@ -75,7 +74,6 @@ 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 sev_active(void) { return false; }
static inline bool sev_es_active(void) { return false; }
static inline bool amd_prot_guest_has(unsigned int attr) { return false; }

diff --git a/arch/x86/kernel/crash_dump_64.c b/arch/x86/kernel/crash_dump_64.c
index 045e82e8945b..0cfe35f03e67 100644
--- a/arch/x86/kernel/crash_dump_64.c
+++ b/arch/x86/kernel/crash_dump_64.c
@@ -10,6 +10,7 @@
#include <linux/crash_dump.h>
#include <linux/uaccess.h>
#include <linux/io.h>
+#include <linux/protected_guest.h>

static ssize_t __copy_oldmem_page(unsigned long pfn, char *buf, size_t csize,
unsigned long offset, int userbuf,
@@ -73,5 +74,6 @@ ssize_t copy_oldmem_page_encrypted(unsigned long pfn, char *buf, size_t csize,

ssize_t elfcorehdr_read(char *buf, size_t count, u64 *ppos)
{
- return read_from_oldmem(buf, count, ppos, 0, sev_active());
+ return read_from_oldmem(buf, count, ppos, 0,
+ prot_guest_has(PATTR_GUEST_MEM_ENCRYPT));
}
diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c
index a26643dc6bd6..9d08ad2f3faa 100644
--- a/arch/x86/kernel/kvm.c
+++ b/arch/x86/kernel/kvm.c
@@ -27,6 +27,7 @@
#include <linux/nmi.h>
#include <linux/swait.h>
#include <linux/syscore_ops.h>
+#include <linux/protected_guest.h>
#include <asm/timer.h>
#include <asm/cpu.h>
#include <asm/traps.h>
@@ -418,7 +419,7 @@ static void __init sev_map_percpu_data(void)
{
int cpu;

- if (!sev_active())
+ if (!prot_guest_has(PATTR_GUEST_MEM_ENCRYPT))
return;

for_each_possible_cpu(cpu) {
diff --git a/arch/x86/kernel/kvmclock.c b/arch/x86/kernel/kvmclock.c
index ad273e5861c1..f7ba78a23dcd 100644
--- a/arch/x86/kernel/kvmclock.c
+++ b/arch/x86/kernel/kvmclock.c
@@ -16,9 +16,9 @@
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/set_memory.h>
+#include <linux/protected_guest.h>

#include <asm/hypervisor.h>
-#include <asm/mem_encrypt.h>
#include <asm/x86_init.h>
#include <asm/kvmclock.h>

@@ -232,7 +232,7 @@ static void __init kvmclock_init_mem(void)
* hvclock is shared between the guest and the hypervisor, must
* be mapped decrypted.
*/
- if (sev_active()) {
+ if (prot_guest_has(PATTR_GUEST_MEM_ENCRYPT)) {
r = set_memory_decrypted((unsigned long) hvclock_mem,
1UL << order);
if (r) {
diff --git a/arch/x86/kernel/machine_kexec_64.c b/arch/x86/kernel/machine_kexec_64.c
index 8e7b517ad738..66ff788b79c9 100644
--- a/arch/x86/kernel/machine_kexec_64.c
+++ b/arch/x86/kernel/machine_kexec_64.c
@@ -167,7 +167,7 @@ static int init_transition_pgtable(struct kimage *image, pgd_t *pgd)
}
pte = pte_offset_kernel(pmd, vaddr);

- if (sev_active())
+ if (prot_guest_has(PATTR_GUEST_MEM_ENCRYPT))
prot = PAGE_KERNEL_EXEC;

set_pte(pte, pfn_pte(paddr >> PAGE_SHIFT, prot));
@@ -207,7 +207,7 @@ static int init_pgtable(struct kimage *image, unsigned long start_pgtable)
level4p = (pgd_t *)__va(start_pgtable);
clear_page(level4p);

- if (sev_active()) {
+ if (prot_guest_has(PATTR_GUEST_MEM_ENCRYPT)) {
info.page_flag |= _PAGE_ENC;
info.kernpg_flag |= _PAGE_ENC;
}
@@ -570,12 +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 (!prot_guest_has(PATTR_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);
@@ -583,12 +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 (!prot_guest_has(PATTR_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/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index e8ccab50ebf6..b69f5ac622d5 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -25,6 +25,7 @@
#include <linux/pagemap.h>
#include <linux/swap.h>
#include <linux/rwsem.h>
+#include <linux/protected_guest.h>

#include <asm/apic.h>
#include <asm/perf_event.h>
@@ -457,7 +458,7 @@ static int has_svm(void)
return 0;
}

- if (sev_active()) {
+ if (prot_guest_has(PATTR_SEV)) {
pr_info("KVM is unsupported when running as an SEV guest\n");
return 0;
}
diff --git a/arch/x86/mm/ioremap.c b/arch/x86/mm/ioremap.c
index 583afd54c7e1..3ed0f28f12af 100644
--- a/arch/x86/mm/ioremap.c
+++ b/arch/x86/mm/ioremap.c
@@ -92,7 +92,7 @@ static unsigned int __ioremap_check_ram(struct resource *res)
*/
static unsigned int __ioremap_check_encrypted(struct resource *res)
{
- if (!sev_active())
+ if (!prot_guest_has(PATTR_GUEST_MEM_ENCRYPT))
return 0;

switch (res->desc) {
@@ -112,7 +112,7 @@ static unsigned int __ioremap_check_encrypted(struct resource *res)
*/
static void __ioremap_check_other(resource_size_t addr, struct ioremap_desc *desc)
{
- if (!sev_active())
+ if (!prot_guest_has(PATTR_GUEST_MEM_ENCRYPT))
return;

if (!IS_ENABLED(CONFIG_EFI))
@@ -556,7 +556,7 @@ static bool memremap_should_map_decrypted(resource_size_t phys_addr,
case E820_TYPE_NVS:
case E820_TYPE_UNUSABLE:
/* For SEV, these areas are encrypted */
- if (sev_active())
+ if (prot_guest_has(PATTR_GUEST_MEM_ENCRYPT))
break;
fallthrough;

diff --git a/arch/x86/mm/mem_encrypt.c b/arch/x86/mm/mem_encrypt.c
index 5635ca9a1fbe..83bc928f529e 100644
--- a/arch/x86/mm/mem_encrypt.c
+++ b/arch/x86/mm/mem_encrypt.c
@@ -194,7 +194,7 @@ void __init sme_early_init(void)
for (i = 0; i < ARRAY_SIZE(protection_map); i++)
protection_map[i] = pgprot_encrypted(protection_map[i]);

- if (sev_active())
+ if (amd_prot_guest_has(PATTR_SEV))
swiotlb_force = SWIOTLB_FORCE;
}

@@ -203,7 +203,7 @@ void __init sev_setup_arch(void)
phys_addr_t total_mem = memblock_phys_mem_size();
unsigned long size;

- if (!sev_active())
+ if (!amd_prot_guest_has(PATTR_SEV))
return;

/*
@@ -373,7 +373,7 @@ int __init early_set_memory_encrypted(unsigned long vaddr, unsigned long size)
* up under SME the trampoline area cannot be encrypted, whereas under SEV
* the trampoline area must be encrypted.
*/
-bool sev_active(void)
+static bool sev_active(void)
{
return sev_status & MSR_AMD64_SEV_ENABLED;
}
@@ -382,7 +382,6 @@ static bool sme_active(void)
{
return sme_me_mask && !sev_active();
}
-EXPORT_SYMBOL_GPL(sev_active);

/* Needs to be called from non-instrumentable code */
bool noinstr sev_es_active(void)
@@ -420,7 +419,7 @@ bool force_dma_unencrypted(struct device *dev)
/*
* For SEV, all DMA must be to unencrypted addresses.
*/
- if (sev_active())
+ if (amd_prot_guest_has(PATTR_SEV))
return true;

/*
@@ -479,7 +478,7 @@ static void print_mem_encrypt_feature_info(void)
}

/* Secure Encrypted Virtualization */
- if (sev_active())
+ if (amd_prot_guest_has(PATTR_SEV))
pr_cont(" SEV");

/* Encrypted Register State */
@@ -502,7 +501,7 @@ void __init mem_encrypt_init(void)
* With SEV, we need to unroll the rep string I/O instructions,
* but SEV-ES supports them through the #VC handler.
*/
- if (sev_active() && !sev_es_active())
+ if (amd_prot_guest_has(PATTR_SEV) && !sev_es_active())
static_branch_enable(&sev_enable_key);

print_mem_encrypt_feature_info();
@@ -510,6 +509,6 @@ void __init mem_encrypt_init(void)

int arch_has_restricted_virtio_memory_access(void)
{
- return sev_active();
+ return amd_prot_guest_has(PATTR_SEV);
}
EXPORT_SYMBOL_GPL(arch_has_restricted_virtio_memory_access);
diff --git a/arch/x86/platform/efi/efi_64.c b/arch/x86/platform/efi/efi_64.c
index 7515e78ef898..94737fcc1e21 100644
--- a/arch/x86/platform/efi/efi_64.c
+++ b/arch/x86/platform/efi/efi_64.c
@@ -33,7 +33,7 @@
#include <linux/reboot.h>
#include <linux/slab.h>
#include <linux/ucs2_string.h>
-#include <linux/mem_encrypt.h>
+#include <linux/protected_guest.h>
#include <linux/sched/task.h>

#include <asm/setup.h>
@@ -284,7 +284,8 @@ static void __init __map_region(efi_memory_desc_t *md, u64 va)
if (!(md->attribute & EFI_MEMORY_WB))
flags |= _PAGE_PCD;

- if (sev_active() && md->type != EFI_MEMORY_MAPPED_IO)
+ if (prot_guest_has(PATTR_GUEST_MEM_ENCRYPT) &&
+ md->type != EFI_MEMORY_MAPPED_IO)
flags |= _PAGE_ENC;

pfn = md->phys_addr >> PAGE_SHIFT;
@@ -390,7 +391,7 @@ static int __init efi_update_mem_attr(struct mm_struct *mm, efi_memory_desc_t *m
if (!(md->attribute & EFI_MEMORY_RO))
pf |= _PAGE_RW;

- if (sev_active())
+ if (prot_guest_has(PATTR_GUEST_MEM_ENCRYPT))
pf |= _PAGE_ENC;

return efi_update_mappings(md, pf);
@@ -438,7 +439,7 @@ void __init efi_runtime_update_mappings(void)
(md->type != EFI_RUNTIME_SERVICES_CODE))
pf |= _PAGE_RW;

- if (sev_active())
+ if (prot_guest_has(PATTR_GUEST_MEM_ENCRYPT))
pf |= _PAGE_ENC;

efi_update_mappings(md, pf);
--
2.32.0