1 files changed, 49 insertions, 3 deletions

diff --git a/arch/x86/kernel/kvmclock.c b/arch/x86/kernel/kvmclock.c
index 1e6764648af3..013fe3d21dbb 100644
--- a/arch/x86/kernel/kvmclock.c
+++ b/arch/x86/kernel/kvmclock.c
@@ -28,6 +28,7 @@
 #include <linux/sched/clock.h>
 #include <linux/mm.h>
 #include <linux/slab.h>
+#include <linux/set_memory.h>
 
 #include <asm/hypervisor.h>
 #include <asm/mem_encrypt.h>
@@ -61,9 +62,10 @@ early_param("no-kvmclock-vsyscall", parse_no_kvmclock_vsyscall);
         (PAGE_SIZE / sizeof(struct pvclock_vsyscall_time_info))
 
 static struct pvclock_vsyscall_time_info
-                        hv_clock_boot[HVC_BOOT_ARRAY_SIZE] __aligned(PAGE_SIZE);
-static struct pvclock_wall_clock wall_clock;
+                        hv_clock_boot[HVC_BOOT_ARRAY_SIZE] __bss_decrypted __aligned(PAGE_SIZE);
+static struct pvclock_wall_clock wall_clock __bss_decrypted;
 static DEFINE_PER_CPU(struct pvclock_vsyscall_time_info *, hv_clock_per_cpu);
+static struct pvclock_vsyscall_time_info *hvclock_mem;
 
 static inline struct pvclock_vcpu_time_info *this_cpu_pvti(void)
 {
@@ -236,6 +238,45 @@ static void kvm_shutdown(void)
         native_machine_shutdown();
 }
 
+static void __init kvmclock_init_mem(void)
+{
+        unsigned long ncpus;
+        unsigned int order;
+        struct page *p;
+        int r;
+
+        if (HVC_BOOT_ARRAY_SIZE >= num_possible_cpus())
+                return;
+
+        ncpus = num_possible_cpus() - HVC_BOOT_ARRAY_SIZE;
+        order = get_order(ncpus * sizeof(*hvclock_mem));
+
+        p = alloc_pages(GFP_KERNEL, order);
+        if (!p) {
+                pr_warn("%s: failed to alloc %d pages", __func__, (1U << order));
+                return;
+        }
+
+        hvclock_mem = page_address(p);
+
+        /*
+         * hvclock is shared between the guest and the hypervisor, must
+         * be mapped decrypted.
+         */
+        if (sev_active()) {
+                r = set_memory_decrypted((unsigned long) hvclock_mem,
+                                         1UL << order);
+                if (r) {
+                        __free_pages(p, order);
+                        hvclock_mem = NULL;
+                        pr_warn("kvmclock: set_memory_decrypted() failed. Disabling\n");
+                        return;
+                }
+        }
+
+        memset(hvclock_mem, 0, PAGE_SIZE << order);
+}
+
 static int __init kvm_setup_vsyscall_timeinfo(void)
 {
 #ifdef CONFIG_X86_64
@@ -250,6 +291,9 @@ static int __init kvm_setup_vsyscall_timeinfo(void)
 
         kvm_clock.archdata.vclock_mode = VCLOCK_PVCLOCK;
 #endif
+
+        kvmclock_init_mem();
+
         return 0;
 }
 early_initcall(kvm_setup_vsyscall_timeinfo);
@@ -269,8 +313,10 @@ static int kvmclock_setup_percpu(unsigned int cpu)
         /* Use the static page for the first CPUs, allocate otherwise */
         if (cpu < HVC_BOOT_ARRAY_SIZE)
                 p = &hv_clock_boot[cpu];
+        else if (hvclock_mem)
+                p = hvclock_mem + cpu - HVC_BOOT_ARRAY_SIZE;
         else
-                p = kzalloc(sizeof(*p), GFP_KERNEL);
+                return -ENOMEM;
 
         per_cpu(hv_clock_per_cpu, cpu) = p;
         return p ? 0 : -ENOMEM;