diff mbox series

[V4,01/13] x86/hyperv: Initialize GHCB page in Isolation VM

Message ID 20210827172114.414281-2-ltykernel@gmail.com
State Superseded
Headers show
Series [V4,01/13] x86/hyperv: Initialize GHCB page in Isolation VM | expand

Commit Message

Tianyu Lan Aug. 27, 2021, 5:20 p.m. UTC 
From: Tianyu Lan <Tianyu.Lan@microsoft.com>

Hyperv exposes GHCB page via SEV ES GHCB MSR for SNP guest
to communicate with hypervisor. Map GHCB page for all
cpus to read/write MSR register and submit hvcall request
via ghcb page.

Signed-off-by: Tianyu Lan <Tianyu.Lan@microsoft.com>
---
Chagne since v3:
        * Rename ghcb_base to hv_ghcb_pg and move it out of
	  struct ms_hyperv_info.
	* Allocate hv_ghcb_pg before cpuhp_setup_state() and leverage
	  hv_cpu_init() to initialize ghcb page.
---
 arch/x86/hyperv/hv_init.c       | 68 +++++++++++++++++++++++++++++----
 arch/x86/include/asm/mshyperv.h |  4 ++
 arch/x86/kernel/cpu/mshyperv.c  |  3 ++
 include/asm-generic/mshyperv.h  |  1 +
 4 files changed, 69 insertions(+), 7 deletions(-)

Comments

Michael Kelley Sept. 2, 2021, 12:15 a.m. UTC | #1 
From: Tianyu Lan <ltykernel@gmail.com> Sent: Friday, August 27, 2021 10:21 AM

> 

> Hyperv exposes GHCB page via SEV ES GHCB MSR for SNP guest

> to communicate with hypervisor. Map GHCB page for all

> cpus to read/write MSR register and submit hvcall request

> via ghcb page.

> 

> Signed-off-by: Tianyu Lan <Tianyu.Lan@microsoft.com>

> ---

> Chagne since v3:

>         * Rename ghcb_base to hv_ghcb_pg and move it out of

> 	  struct ms_hyperv_info.

> 	* Allocate hv_ghcb_pg before cpuhp_setup_state() and leverage

> 	  hv_cpu_init() to initialize ghcb page.

> ---

>  arch/x86/hyperv/hv_init.c       | 68 +++++++++++++++++++++++++++++----

>  arch/x86/include/asm/mshyperv.h |  4 ++

>  arch/x86/kernel/cpu/mshyperv.c  |  3 ++

>  include/asm-generic/mshyperv.h  |  1 +

>  4 files changed, 69 insertions(+), 7 deletions(-)

> 

> diff --git a/arch/x86/hyperv/hv_init.c b/arch/x86/hyperv/hv_init.c

> index 708a2712a516..eba10ed4f73e 100644

> --- a/arch/x86/hyperv/hv_init.c

> +++ b/arch/x86/hyperv/hv_init.c

> @@ -20,6 +20,7 @@

>  #include <linux/kexec.h>

>  #include <linux/version.h>

>  #include <linux/vmalloc.h>

> +#include <linux/io.h>

>  #include <linux/mm.h>

>  #include <linux/hyperv.h>

>  #include <linux/slab.h>

> @@ -36,12 +37,42 @@ EXPORT_SYMBOL_GPL(hv_current_partition_id);

>  void *hv_hypercall_pg;

>  EXPORT_SYMBOL_GPL(hv_hypercall_pg);

> 

> +void __percpu **hv_ghcb_pg;

> +

>  /* Storage to save the hypercall page temporarily for hibernation */

>  static void *hv_hypercall_pg_saved;

> 

>  struct hv_vp_assist_page **hv_vp_assist_page;

>  EXPORT_SYMBOL_GPL(hv_vp_assist_page);

> 

> +static int hyperv_init_ghcb(void)

> +{

> +	u64 ghcb_gpa;

> +	void *ghcb_va;

> +	void **ghcb_base;

> +

> +	if (!hv_isolation_type_snp())

> +		return 0;

> +

> +	if (!hv_ghcb_pg)

> +		return -EINVAL;

> +

> +	/*

> +	 * GHCB page is allocated by paravisor. The address

> +	 * returned by MSR_AMD64_SEV_ES_GHCB is above shared

> +	 * ghcb boundary and map it here.


I'm not sure what the "shared ghcb boundary" is.  Did you
mean "shared_gpa_boundary"?

> +	 */

> +	rdmsrl(MSR_AMD64_SEV_ES_GHCB, ghcb_gpa);

> +	ghcb_va = memremap(ghcb_gpa, HV_HYP_PAGE_SIZE, MEMREMAP_WB);

> +	if (!ghcb_va)

> +		return -ENOMEM;

> +

> +	ghcb_base = (void **)this_cpu_ptr(hv_ghcb_pg);

> +	*ghcb_base = ghcb_va;

> +

> +	return 0;

> +}

> +

>  static int hv_cpu_init(unsigned int cpu)

>  {

>  	union hv_vp_assist_msr_contents msr = { 0 };

> @@ -85,7 +116,7 @@ static int hv_cpu_init(unsigned int cpu)

>  		}

>  	}

> 

> -	return 0;

> +	return hyperv_init_ghcb();

>  }

> 

>  static void (*hv_reenlightenment_cb)(void);

> @@ -177,6 +208,14 @@ static int hv_cpu_die(unsigned int cpu)

>  {

>  	struct hv_reenlightenment_control re_ctrl;

>  	unsigned int new_cpu;

> +	void **ghcb_va;

> +

> +	if (hv_ghcb_pg) {

> +		ghcb_va = (void **)this_cpu_ptr(hv_ghcb_pg);

> +		if (*ghcb_va)

> +			memunmap(*ghcb_va);

> +		*ghcb_va = NULL;

> +	}

> 

>  	hv_common_cpu_die(cpu);

> 

> @@ -366,10 +405,16 @@ void __init hyperv_init(void)

>  		goto common_free;

>  	}

> 

> +	if (hv_isolation_type_snp()) {

> +		hv_ghcb_pg = alloc_percpu(void *);

> +		if (!hv_ghcb_pg)

> +			goto free_vp_assist_page;

> +	}

> +

>  	cpuhp = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "x86/hyperv_init:online",

>  				  hv_cpu_init, hv_cpu_die);

>  	if (cpuhp < 0)

> -		goto free_vp_assist_page;

> +		goto free_ghcb_page;

> 

>  	/*

>  	 * Setup the hypercall page and enable hypercalls.

> @@ -383,10 +428,8 @@ void __init hyperv_init(void)

>  			VMALLOC_END, GFP_KERNEL, PAGE_KERNEL_ROX,

>  			VM_FLUSH_RESET_PERMS, NUMA_NO_NODE,

>  			__builtin_return_address(0));

> -	if (hv_hypercall_pg == NULL) {

> -		wrmsrl(HV_X64_MSR_GUEST_OS_ID, 0);

> -		goto remove_cpuhp_state;

> -	}

> +	if (hv_hypercall_pg == NULL)

> +		goto clean_guest_os_id;

> 

>  	rdmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);

>  	hypercall_msr.enable = 1;

> @@ -456,8 +499,11 @@ void __init hyperv_init(void)

>  	hv_query_ext_cap(0);

>  	return;

> 

> -remove_cpuhp_state:

> +clean_guest_os_id:

> +	wrmsrl(HV_X64_MSR_GUEST_OS_ID, 0);

>  	cpuhp_remove_state(cpuhp);

> +free_ghcb_page:

> +	free_percpu(hv_ghcb_pg);

>  free_vp_assist_page:

>  	kfree(hv_vp_assist_page);

>  	hv_vp_assist_page = NULL;

> @@ -559,3 +605,11 @@ bool hv_is_isolation_supported(void)

>  {

>  	return hv_get_isolation_type() != HV_ISOLATION_TYPE_NONE;

>  }

> +

> +DEFINE_STATIC_KEY_FALSE(isolation_type_snp);

> +

> +bool hv_isolation_type_snp(void)

> +{

> +	return static_branch_unlikely(&isolation_type_snp);

> +}

> +EXPORT_SYMBOL_GPL(hv_isolation_type_snp);

> diff --git a/arch/x86/include/asm/mshyperv.h b/arch/x86/include/asm/mshyperv.h

> index adccbc209169..37739a277ac6 100644

> --- a/arch/x86/include/asm/mshyperv.h

> +++ b/arch/x86/include/asm/mshyperv.h

> @@ -11,6 +11,8 @@

>  #include <asm/paravirt.h>

>  #include <asm/mshyperv.h>

> 

> +DECLARE_STATIC_KEY_FALSE(isolation_type_snp);

> +

>  typedef int (*hyperv_fill_flush_list_func)(

>  		struct hv_guest_mapping_flush_list *flush,

>  		void *data);

> @@ -39,6 +41,8 @@ extern void *hv_hypercall_pg;

> 

>  extern u64 hv_current_partition_id;

> 

> +extern void __percpu **hv_ghcb_pg;

> +

>  int hv_call_deposit_pages(int node, u64 partition_id, u32 num_pages);

>  int hv_call_add_logical_proc(int node, u32 lp_index, u32 acpi_id);

>  int hv_call_create_vp(int node, u64 partition_id, u32 vp_index, u32 flags);

> diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c

> index 6b5835a087a3..20557a9d6e25 100644

> --- a/arch/x86/kernel/cpu/mshyperv.c

> +++ b/arch/x86/kernel/cpu/mshyperv.c

> @@ -316,6 +316,9 @@ static void __init ms_hyperv_init_platform(void)

> 

>  		pr_info("Hyper-V: Isolation Config: Group A 0x%x, Group B 0x%x\n",

>  			ms_hyperv.isolation_config_a, ms_hyperv.isolation_config_b);

> +

> +		if (hv_get_isolation_type() == HV_ISOLATION_TYPE_SNP)

> +			static_branch_enable(&isolation_type_snp);

>  	}

> 

>  	if (hv_max_functions_eax >= HYPERV_CPUID_NESTED_FEATURES) {

> diff --git a/include/asm-generic/mshyperv.h b/include/asm-generic/mshyperv.h

> index c1ab6a6e72b5..0924bbd8458e 100644

> --- a/include/asm-generic/mshyperv.h

> +++ b/include/asm-generic/mshyperv.h

> @@ -237,6 +237,7 @@ bool hv_is_hyperv_initialized(void);

>  bool hv_is_hibernation_supported(void);

>  enum hv_isolation_type hv_get_isolation_type(void);

>  bool hv_is_isolation_supported(void);

> +bool hv_isolation_type_snp(void);

>  void hyperv_cleanup(void);

>  bool hv_query_ext_cap(u64 cap_query);

>  #else /* CONFIG_HYPERV */

> --

> 2.25.1
diff mbox series

Patch

diff --git a/arch/x86/hyperv/hv_init.c b/arch/x86/hyperv/hv_init.c
index 708a2712a516..eba10ed4f73e 100644
--- a/arch/x86/hyperv/hv_init.c
+++ b/arch/x86/hyperv/hv_init.c
@@ -20,6 +20,7 @@ 
 #include <linux/kexec.h>
 #include <linux/version.h>
 #include <linux/vmalloc.h>
+#include <linux/io.h>
 #include <linux/mm.h>
 #include <linux/hyperv.h>
 #include <linux/slab.h>
@@ -36,12 +37,42 @@  EXPORT_SYMBOL_GPL(hv_current_partition_id);
 void *hv_hypercall_pg;
 EXPORT_SYMBOL_GPL(hv_hypercall_pg);
 
+void __percpu **hv_ghcb_pg;
+
 /* Storage to save the hypercall page temporarily for hibernation */
 static void *hv_hypercall_pg_saved;
 
 struct hv_vp_assist_page **hv_vp_assist_page;
 EXPORT_SYMBOL_GPL(hv_vp_assist_page);
 
+static int hyperv_init_ghcb(void)
+{
+	u64 ghcb_gpa;
+	void *ghcb_va;
+	void **ghcb_base;
+
+	if (!hv_isolation_type_snp())
+		return 0;
+
+	if (!hv_ghcb_pg)
+		return -EINVAL;
+
+	/*
+	 * GHCB page is allocated by paravisor. The address
+	 * returned by MSR_AMD64_SEV_ES_GHCB is above shared
+	 * ghcb boundary and map it here.
+	 */
+	rdmsrl(MSR_AMD64_SEV_ES_GHCB, ghcb_gpa);
+	ghcb_va = memremap(ghcb_gpa, HV_HYP_PAGE_SIZE, MEMREMAP_WB);
+	if (!ghcb_va)
+		return -ENOMEM;
+
+	ghcb_base = (void **)this_cpu_ptr(hv_ghcb_pg);
+	*ghcb_base = ghcb_va;
+
+	return 0;
+}
+
 static int hv_cpu_init(unsigned int cpu)
 {
 	union hv_vp_assist_msr_contents msr = { 0 };
@@ -85,7 +116,7 @@  static int hv_cpu_init(unsigned int cpu)
 		}
 	}
 
-	return 0;
+	return hyperv_init_ghcb();
 }
 
 static void (*hv_reenlightenment_cb)(void);
@@ -177,6 +208,14 @@  static int hv_cpu_die(unsigned int cpu)
 {
 	struct hv_reenlightenment_control re_ctrl;
 	unsigned int new_cpu;
+	void **ghcb_va;
+
+	if (hv_ghcb_pg) {
+		ghcb_va = (void **)this_cpu_ptr(hv_ghcb_pg);
+		if (*ghcb_va)
+			memunmap(*ghcb_va);
+		*ghcb_va = NULL;
+	}
 
 	hv_common_cpu_die(cpu);
 
@@ -366,10 +405,16 @@  void __init hyperv_init(void)
 		goto common_free;
 	}
 
+	if (hv_isolation_type_snp()) {
+		hv_ghcb_pg = alloc_percpu(void *);
+		if (!hv_ghcb_pg)
+			goto free_vp_assist_page;
+	}
+
 	cpuhp = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "x86/hyperv_init:online",
 				  hv_cpu_init, hv_cpu_die);
 	if (cpuhp < 0)
-		goto free_vp_assist_page;
+		goto free_ghcb_page;
 
 	/*
 	 * Setup the hypercall page and enable hypercalls.
@@ -383,10 +428,8 @@  void __init hyperv_init(void)
 			VMALLOC_END, GFP_KERNEL, PAGE_KERNEL_ROX,
 			VM_FLUSH_RESET_PERMS, NUMA_NO_NODE,
 			__builtin_return_address(0));
-	if (hv_hypercall_pg == NULL) {
-		wrmsrl(HV_X64_MSR_GUEST_OS_ID, 0);
-		goto remove_cpuhp_state;
-	}
+	if (hv_hypercall_pg == NULL)
+		goto clean_guest_os_id;
 
 	rdmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
 	hypercall_msr.enable = 1;
@@ -456,8 +499,11 @@  void __init hyperv_init(void)
 	hv_query_ext_cap(0);
 	return;
 
-remove_cpuhp_state:
+clean_guest_os_id:
+	wrmsrl(HV_X64_MSR_GUEST_OS_ID, 0);
 	cpuhp_remove_state(cpuhp);
+free_ghcb_page:
+	free_percpu(hv_ghcb_pg);
 free_vp_assist_page:
 	kfree(hv_vp_assist_page);
 	hv_vp_assist_page = NULL;
@@ -559,3 +605,11 @@  bool hv_is_isolation_supported(void)
 {
 	return hv_get_isolation_type() != HV_ISOLATION_TYPE_NONE;
 }
+
+DEFINE_STATIC_KEY_FALSE(isolation_type_snp);
+
+bool hv_isolation_type_snp(void)
+{
+	return static_branch_unlikely(&isolation_type_snp);
+}
+EXPORT_SYMBOL_GPL(hv_isolation_type_snp);
diff --git a/arch/x86/include/asm/mshyperv.h b/arch/x86/include/asm/mshyperv.h
index adccbc209169..37739a277ac6 100644
--- a/arch/x86/include/asm/mshyperv.h
+++ b/arch/x86/include/asm/mshyperv.h
@@ -11,6 +11,8 @@ 
 #include <asm/paravirt.h>
 #include <asm/mshyperv.h>
 
+DECLARE_STATIC_KEY_FALSE(isolation_type_snp);
+
 typedef int (*hyperv_fill_flush_list_func)(
 		struct hv_guest_mapping_flush_list *flush,
 		void *data);
@@ -39,6 +41,8 @@  extern void *hv_hypercall_pg;
 
 extern u64 hv_current_partition_id;
 
+extern void __percpu **hv_ghcb_pg;
+
 int hv_call_deposit_pages(int node, u64 partition_id, u32 num_pages);
 int hv_call_add_logical_proc(int node, u32 lp_index, u32 acpi_id);
 int hv_call_create_vp(int node, u64 partition_id, u32 vp_index, u32 flags);
diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c
index 6b5835a087a3..20557a9d6e25 100644
--- a/arch/x86/kernel/cpu/mshyperv.c
+++ b/arch/x86/kernel/cpu/mshyperv.c
@@ -316,6 +316,9 @@  static void __init ms_hyperv_init_platform(void)
 
 		pr_info("Hyper-V: Isolation Config: Group A 0x%x, Group B 0x%x\n",
 			ms_hyperv.isolation_config_a, ms_hyperv.isolation_config_b);
+
+		if (hv_get_isolation_type() == HV_ISOLATION_TYPE_SNP)
+			static_branch_enable(&isolation_type_snp);
 	}
 
 	if (hv_max_functions_eax >= HYPERV_CPUID_NESTED_FEATURES) {
diff --git a/include/asm-generic/mshyperv.h b/include/asm-generic/mshyperv.h
index c1ab6a6e72b5..0924bbd8458e 100644
--- a/include/asm-generic/mshyperv.h
+++ b/include/asm-generic/mshyperv.h
@@ -237,6 +237,7 @@  bool hv_is_hyperv_initialized(void);
 bool hv_is_hibernation_supported(void);
 enum hv_isolation_type hv_get_isolation_type(void);
 bool hv_is_isolation_supported(void);
+bool hv_isolation_type_snp(void);
 void hyperv_cleanup(void);
 bool hv_query_ext_cap(u64 cap_query);
 #else /* CONFIG_HYPERV */