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

Commit Message

Kalra, Ashish Dec. 1, 2020, 12:48 a.m. UTC

From: Ashish Kalra <[e-mail]>

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 <[e-mail]>
---
 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(+)

Patch

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