[PATCH v14 01/25] x86/kvmclock: Remove memblock dependency

[Pavel Tatashin]

KVM clock is initialized later compared to other hypervisor clocks because
it has a dependency on the memblock allocator.

Bring it in line with other hypervisors by using memory from the BSS
instead of allocating it.

The benefits:

  - Remove ifdef from common code
  - Earlier availability of the clock
  - Remove dependency on memblock, and reduce code

The downside:

  - Static allocation of the per cpu data structures sized NR_CPUS * 64byte
Will be addressed in follow up patches.

[ tglx: Split out from larger series ]

Signed-off-by: Pavel Tatashin 
Signed-off-by: Thomas Gleixner 
Acked-by: Paolo Bonzini 
---
 arch/x86/kernel/kvm.c  |  1 +
 arch/x86/kernel/kvmclock.c | 66 +++---
 arch/x86/kernel/setup.c|  4 ---
 3 files changed, 12 insertions(+), 59 deletions(-)

diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c
index 5b2300b818af..c65c232d3ddd 100644
--- a/arch/x86/kernel/kvm.c
+++ b/arch/x86/kernel/kvm.c
@@ -628,6 +628,7 @@ const __initconst struct hypervisor_x86 x86_hyper_kvm = {
.name   = "KVM",
.detect = kvm_detect,
.type   = X86_HYPER_KVM,
+   .init.init_platform = kvmclock_init,
.init.guest_late_init   = kvm_guest_init,
.init.x2apic_available  = kvm_para_available,
 };
diff --git a/arch/x86/kernel/kvmclock.c b/arch/x86/kernel/kvmclock.c
index bf8d1eb7fca3..890e9e58e4bf 100644
--- a/arch/x86/kernel/kvmclock.c
+++ b/arch/x86/kernel/kvmclock.c
@@ -23,9 +23,9 @@
 #include 
 #include 
 #include 
-#include 
 #include 
 #include 
+#include 
 
 #include 
 #include 
@@ -44,6 +44,13 @@ static int parse_no_kvmclock(char *arg)
 }
 early_param("no-kvmclock", parse_no_kvmclock);
 
+/* Aligned to page sizes to match whats mapped via vsyscalls to userspace */
+#define HV_CLOCK_SIZE  (sizeof(struct pvclock_vsyscall_time_info) * NR_CPUS)
+#define WALL_CLOCK_SIZE(sizeof(struct pvclock_wall_clock))
+
+static u8 hv_clock_mem[PAGE_ALIGN(HV_CLOCK_SIZE)] __aligned(PAGE_SIZE);
+static u8 wall_clock_mem[PAGE_ALIGN(WALL_CLOCK_SIZE)] __aligned(PAGE_SIZE);
+
 /* The hypervisor will put information about time periodically here */
 static struct pvclock_vsyscall_time_info *hv_clock;
 static struct pvclock_wall_clock *wall_clock;
@@ -244,43 +251,12 @@ static void kvm_shutdown(void)
native_machine_shutdown();
 }
 
-static phys_addr_t __init kvm_memblock_alloc(phys_addr_t size,
-phys_addr_t align)
-{
-   phys_addr_t mem;
-
-   mem = memblock_alloc(size, align);
-   if (!mem)
-   return 0;
-
-   if (sev_active()) {
-   if (early_set_memory_decrypted((unsigned long)__va(mem), size))
-   goto e_free;
-   }
-
-   return mem;
-e_free:
-   memblock_free(mem, size);
-   return 0;
-}
-
-static void __init kvm_memblock_free(phys_addr_t addr, phys_addr_t size)
-{
-   if (sev_active())
-   early_set_memory_encrypted((unsigned long)__va(addr), size);
-
-   memblock_free(addr, size);
-}
-
 void __init kvmclock_init(void)
 {
struct pvclock_vcpu_time_info *vcpu_time;
-   unsigned long mem, mem_wall_clock;
-   int size, cpu, wall_clock_size;
+   int cpu;
u8 flags;
 
-   size = PAGE_ALIGN(sizeof(struct pvclock_vsyscall_time_info)*NR_CPUS);
-
if (!kvm_para_available())
return;
 
@@ -290,28 +266,11 @@ void __init kvmclock_init(void)
} else if (!(kvmclock && kvm_para_has_feature(KVM_FEATURE_CLOCKSOURCE)))
return;
 
-   wall_clock_size = PAGE_ALIGN(sizeof(struct pvclock_wall_clock));
-   mem_wall_clock = kvm_memblock_alloc(wall_clock_size, PAGE_SIZE);
-   if (!mem_wall_clock)
-   return;
-
-   wall_clock = __va(mem_wall_clock);
-   memset(wall_clock, 0, wall_clock_size);
-
-   mem = kvm_memblock_alloc(size, PAGE_SIZE);
-   if (!mem) {
-   kvm_memblock_free(mem_wall_clock, wall_clock_size);
-   wall_clock = NULL;
-   return;
-   }
-
-   hv_clock = __va(mem);
-   memset(hv_clock, 0, size);
+   wall_clock = (struct pvclock_wall_clock *)wall_clock_mem;
+   hv_clock = (struct pvclock_vsyscall_time_info *)hv_clock_mem;
 
if (kvm_register_clock("primary cpu clock")) {
hv_clock = NULL;
-   kvm_memblock_free(mem, size);
-   kvm_memblock_free(mem_wall_clock, wall_clock_size);
wall_clock = NULL;
return;
}
@@ -354,13 +313,10 @@ int __init kvm_setup_vsyscall_timeinfo(void)
int cpu;
u8 flags;
struct pvclock_vcpu_time_info *vcpu_time;
-   unsigned int size;
 
if (!hv_clock)
return 0;
 
-   size = PAGE_ALIGN(sizeof(struct pvclock_vsyscall_time_info)*NR_CPUS);
-
cpu = get_cpu();
 
vcpu_time = _clock[cpu].pvti;
diff --git 

[PATCH v14 01/25] x86/kvmclock: Remove memblock dependency

[Pavel Tatashin]

KVM clock is initialized later compared to other hypervisor clocks because
it has a dependency on the memblock allocator.

Bring it in line with other hypervisors by using memory from the BSS
instead of allocating it.

The benefits:

  - Remove ifdef from common code
  - Earlier availability of the clock
  - Remove dependency on memblock, and reduce code

The downside:

  - Static allocation of the per cpu data structures sized NR_CPUS * 64byte
Will be addressed in follow up patches.

[ tglx: Split out from larger series ]

Signed-off-by: Pavel Tatashin 
Signed-off-by: Thomas Gleixner 
Acked-by: Paolo Bonzini 
---
 arch/x86/kernel/kvm.c  |  1 +
 arch/x86/kernel/kvmclock.c | 66 +++---
 arch/x86/kernel/setup.c|  4 ---
 3 files changed, 12 insertions(+), 59 deletions(-)

diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c
index 5b2300b818af..c65c232d3ddd 100644
--- a/arch/x86/kernel/kvm.c
+++ b/arch/x86/kernel/kvm.c
@@ -628,6 +628,7 @@ const __initconst struct hypervisor_x86 x86_hyper_kvm = {
.name   = "KVM",
.detect = kvm_detect,
.type   = X86_HYPER_KVM,
+   .init.init_platform = kvmclock_init,
.init.guest_late_init   = kvm_guest_init,
.init.x2apic_available  = kvm_para_available,
 };
diff --git a/arch/x86/kernel/kvmclock.c b/arch/x86/kernel/kvmclock.c
index bf8d1eb7fca3..890e9e58e4bf 100644
--- a/arch/x86/kernel/kvmclock.c
+++ b/arch/x86/kernel/kvmclock.c
@@ -23,9 +23,9 @@
 #include 
 #include 
 #include 
-#include 
 #include 
 #include 
+#include 
 
 #include 
 #include 
@@ -44,6 +44,13 @@ static int parse_no_kvmclock(char *arg)
 }
 early_param("no-kvmclock", parse_no_kvmclock);
 
+/* Aligned to page sizes to match whats mapped via vsyscalls to userspace */
+#define HV_CLOCK_SIZE  (sizeof(struct pvclock_vsyscall_time_info) * NR_CPUS)
+#define WALL_CLOCK_SIZE(sizeof(struct pvclock_wall_clock))
+
+static u8 hv_clock_mem[PAGE_ALIGN(HV_CLOCK_SIZE)] __aligned(PAGE_SIZE);
+static u8 wall_clock_mem[PAGE_ALIGN(WALL_CLOCK_SIZE)] __aligned(PAGE_SIZE);
+
 /* The hypervisor will put information about time periodically here */
 static struct pvclock_vsyscall_time_info *hv_clock;
 static struct pvclock_wall_clock *wall_clock;
@@ -244,43 +251,12 @@ static void kvm_shutdown(void)
native_machine_shutdown();
 }
 
-static phys_addr_t __init kvm_memblock_alloc(phys_addr_t size,
-phys_addr_t align)
-{
-   phys_addr_t mem;
-
-   mem = memblock_alloc(size, align);
-   if (!mem)
-   return 0;
-
-   if (sev_active()) {
-   if (early_set_memory_decrypted((unsigned long)__va(mem), size))
-   goto e_free;
-   }
-
-   return mem;
-e_free:
-   memblock_free(mem, size);
-   return 0;
-}
-
-static void __init kvm_memblock_free(phys_addr_t addr, phys_addr_t size)
-{
-   if (sev_active())
-   early_set_memory_encrypted((unsigned long)__va(addr), size);
-
-   memblock_free(addr, size);
-}
-
 void __init kvmclock_init(void)
 {
struct pvclock_vcpu_time_info *vcpu_time;
-   unsigned long mem, mem_wall_clock;
-   int size, cpu, wall_clock_size;
+   int cpu;
u8 flags;
 
-   size = PAGE_ALIGN(sizeof(struct pvclock_vsyscall_time_info)*NR_CPUS);
-
if (!kvm_para_available())
return;
 
@@ -290,28 +266,11 @@ void __init kvmclock_init(void)
} else if (!(kvmclock && kvm_para_has_feature(KVM_FEATURE_CLOCKSOURCE)))
return;
 
-   wall_clock_size = PAGE_ALIGN(sizeof(struct pvclock_wall_clock));
-   mem_wall_clock = kvm_memblock_alloc(wall_clock_size, PAGE_SIZE);
-   if (!mem_wall_clock)
-   return;
-
-   wall_clock = __va(mem_wall_clock);
-   memset(wall_clock, 0, wall_clock_size);
-
-   mem = kvm_memblock_alloc(size, PAGE_SIZE);
-   if (!mem) {
-   kvm_memblock_free(mem_wall_clock, wall_clock_size);
-   wall_clock = NULL;
-   return;
-   }
-
-   hv_clock = __va(mem);
-   memset(hv_clock, 0, size);
+   wall_clock = (struct pvclock_wall_clock *)wall_clock_mem;
+   hv_clock = (struct pvclock_vsyscall_time_info *)hv_clock_mem;
 
if (kvm_register_clock("primary cpu clock")) {
hv_clock = NULL;
-   kvm_memblock_free(mem, size);
-   kvm_memblock_free(mem_wall_clock, wall_clock_size);
wall_clock = NULL;
return;
}
@@ -354,13 +313,10 @@ int __init kvm_setup_vsyscall_timeinfo(void)
int cpu;
u8 flags;
struct pvclock_vcpu_time_info *vcpu_time;
-   unsigned int size;
 
if (!hv_clock)
return 0;
 
-   size = PAGE_ALIGN(sizeof(struct pvclock_vsyscall_time_info)*NR_CPUS);
-
cpu = get_cpu();
 
vcpu_time = _clock[cpu].pvti;
diff --git