[PATCH v2 7/9] KVM: x86: Mark _bss_decrypted section variables as decrypted in page encryption bitmap.

Ashish Kalra
2020-12-01T00:49:21Z

From: Ashish Kalra <ashish.kalra@amd.com>

Ensure that _bss_decrypted section variables such as hv_clock_boot and
wall_clock are marked as decrypted in the page encryption bitmap if
sev guest is active.

Signed-off-by: Ashish Kalra <ashish.kalra@amd.com>
---
arch/x86/include/asm/mem_encrypt.h | 4 ++++
arch/x86/kernel/kvmclock.c | 12 ++++++++++++
arch/x86/mm/mem_encrypt.c | 6 ++++++
3 files changed, 22 insertions(+)

diff --git a/arch/x86/include/asm/mem_encrypt.h b/arch/x86/include/asm/mem_encrypt.h
index 2f62bbdd9d12..a4fd6a4229eb 100644
--- a/arch/x86/include/asm/mem_encrypt.h
+++ b/arch/x86/include/asm/mem_encrypt.h
@@ -43,6 +43,8 @@ void __init sme_enable(struct boot_params *bp);

int __init early_set_memory_decrypted(unsigned long vaddr, unsigned long size);
int __init early_set_memory_encrypted(unsigned long vaddr, unsigned long size);
+void __init early_set_mem_enc_dec_hypercall(unsigned long vaddr, int npages,
+ bool enc);

void __init mem_encrypt_free_decrypted_mem(void);

@@ -82,6 +84,8 @@ static inline int __init
early_set_memory_decrypted(unsigned long vaddr, unsigned long size) { return 0; }
static inline int __init
early_set_memory_encrypted(unsigned long vaddr, unsigned long size) { return 0; }
+static inline void __init
+early_set_mem_enc_dec_hypercall(unsigned long vaddr, int npages, bool enc) {}

static inline void mem_encrypt_free_decrypted_mem(void) { }

diff --git a/arch/x86/kernel/kvmclock.c b/arch/x86/kernel/kvmclock.c
index aa593743acf6..94a4fbf80e44 100644
--- a/arch/x86/kernel/kvmclock.c
+++ b/arch/x86/kernel/kvmclock.c
@@ -333,6 +333,18 @@ void __init kvmclock_init(void)
pr_info("kvm-clock: Using msrs %x and %x",
msr_kvm_system_time, msr_kvm_wall_clock);

+ if (sev_active()) {
+ unsigned long nr_pages;
+ /*
+ * sizeof(hv_clock_boot) is already PAGE_SIZE aligned
+ */
+ early_set_mem_enc_dec_hypercall((unsigned long)hv_clock_boot,
+ 1, 0);
+ nr_pages = DIV_ROUND_UP(sizeof(wall_clock), PAGE_SIZE);
+ early_set_mem_enc_dec_hypercall((unsigned long)&wall_clock,
+ nr_pages, 0);
+ }
+
this_cpu_write(hv_clock_per_cpu, &hv_clock_boot[0]);
kvm_register_clock("primary cpu clock");
pvclock_set_pvti_cpu0_va(hv_clock_boot);
diff --git a/arch/x86/mm/mem_encrypt.c b/arch/x86/mm/mem_encrypt.c
index 9d1ac65050d0..1bcfbcd2bfd7 100644
--- a/arch/x86/mm/mem_encrypt.c
+++ b/arch/x86/mm/mem_encrypt.c
@@ -376,6 +376,12 @@ int __init early_set_memory_encrypted(unsigned long vaddr, unsigned long size)
return early_set_memory_enc_dec(vaddr, size, true);
}

+void __init early_set_mem_enc_dec_hypercall(unsigned long vaddr, int npages,
+ bool enc)
+{
+ set_memory_enc_dec_hypercall(vaddr, npages, enc);
+}
+
/*
* SME and SEV are very similar but they are not the same, so there are
* times that the kernel will need to distinguish between SME and SEV. The
--
2.17.1