diff mbox series

[RFC,V4,07/17] drivers: hv: Decrypt percpu hvcall input arg page in sev-snp enlightened guest

Message ID 20230403174406.4180472-8-ltykernel@gmail.com
State New
Headers
Series x86/hyperv/sev: Add AMD sev-snp enlightened guest support on hyperv |

Commit Message

Tianyu Lan April 3, 2023, 5:43 p.m. UTC 
  From: Tianyu Lan <tiala@microsoft.com>

Hypervisor needs to access iput arg page and guest should decrypt
the page.

Signed-off-by: Tianyu Lan <tiala@microsoft.com>
---
Change since RFC V3:
	* Use pgcount to decrypt memory.

Change since RFC V2:
	* Set inputarg to be zero after kfree()
	* Not free mem when fail to encrypt mem in the hv_common_cpu_die().
---
 drivers/hv/hv_common.c | 21 ++++++++++++++++++++-
 1 file changed, 20 insertions(+), 1 deletion(-)

Comments

Michael Kelley (LINUX) April 12, 2023, 2:34 p.m. UTC | #1 
From: Tianyu Lan <ltykernel@gmail.com> Sent: Monday, April 3, 2023 10:44 AM
> 
> Hypervisor needs to access iput arg page and guest should decrypt
> the page.
> 
> Signed-off-by: Tianyu Lan <tiala@microsoft.com>
> ---
> Change since RFC V3:
> 	* Use pgcount to decrypt memory.
> 
> Change since RFC V2:
> 	* Set inputarg to be zero after kfree()
> 	* Not free mem when fail to encrypt mem in the hv_common_cpu_die().
> ---
>  drivers/hv/hv_common.c | 21 ++++++++++++++++++++-
>  1 file changed, 20 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/hv/hv_common.c b/drivers/hv/hv_common.c
> index e3b04e978932..455432d49fd3 100644
> --- a/drivers/hv/hv_common.c
> +++ b/drivers/hv/hv_common.c
> @@ -21,6 +21,7 @@
>  #include <linux/ptrace.h>
>  #include <linux/slab.h>
>  #include <linux/dma-map-ops.h>
> +#include <linux/set_memory.h>
>  #include <asm/hyperv-tlfs.h>
>  #include <asm/mshyperv.h>
> 
> @@ -128,6 +129,7 @@ int hv_common_cpu_init(unsigned int cpu)
>  	u64 msr_vp_index;
>  	gfp_t flags;
>  	int pgcount = hv_root_partition ? 2 : 1;
> +	int ret;
> 
>  	/* hv_cpu_init() can be called with IRQs disabled from hv_resume() */
>  	flags = irqs_disabled() ? GFP_ATOMIC : GFP_KERNEL;
> @@ -137,6 +139,17 @@ int hv_common_cpu_init(unsigned int cpu)
>  	if (!(*inputarg))
>  		return -ENOMEM;
> 
> +	if (hv_isolation_type_en_snp()) {
> +		ret = set_memory_decrypted((unsigned long)*inputarg, pgcount);
> +		if (ret) {
> +			kfree(*inputarg);
> +			*inputarg = NULL;
> +			return ret;
> +		}
> +
> +		memset(*inputarg, 0x00, PAGE_SIZE);

The memset() needs to use pgcount * PAGE_SIZE.

> +	}
> +
>  	if (hv_root_partition) {
>  		outputarg = (void **)this_cpu_ptr(hyperv_pcpu_output_arg);
>  		*outputarg = (char *)(*inputarg) + HV_HYP_PAGE_SIZE;
> @@ -156,6 +169,7 @@ int hv_common_cpu_die(unsigned int cpu)
>  {
>  	unsigned long flags;
>  	void **inputarg, **outputarg;
> +	int pgcount = hv_root_partition ? 2 : 1;
>  	void *mem;
> 
>  	local_irq_save(flags);
> @@ -171,7 +185,12 @@ int hv_common_cpu_die(unsigned int cpu)
> 
>  	local_irq_restore(flags);
> 
> -	kfree(mem);
> +	if (hv_isolation_type_en_snp()) {
> +		if (!set_memory_encrypted((unsigned long)mem, pgcount))
> +			kfree(mem);
> +	} else {
> +		kfree(mem);
> +	}
> 
>  	return 0;
>  }
> --
> 2.25.1
diff mbox series

Patch

diff --git a/drivers/hv/hv_common.c b/drivers/hv/hv_common.c
index e3b04e978932..455432d49fd3 100644
--- a/drivers/hv/hv_common.c
+++ b/drivers/hv/hv_common.c
@@ -21,6 +21,7 @@ 
 #include <linux/ptrace.h>
 #include <linux/slab.h>
 #include <linux/dma-map-ops.h>
+#include <linux/set_memory.h>
 #include <asm/hyperv-tlfs.h>
 #include <asm/mshyperv.h>
 
@@ -128,6 +129,7 @@  int hv_common_cpu_init(unsigned int cpu)
 	u64 msr_vp_index;
 	gfp_t flags;
 	int pgcount = hv_root_partition ? 2 : 1;
+	int ret;
 
 	/* hv_cpu_init() can be called with IRQs disabled from hv_resume() */
 	flags = irqs_disabled() ? GFP_ATOMIC : GFP_KERNEL;
@@ -137,6 +139,17 @@  int hv_common_cpu_init(unsigned int cpu)
 	if (!(*inputarg))
 		return -ENOMEM;
 
+	if (hv_isolation_type_en_snp()) {
+		ret = set_memory_decrypted((unsigned long)*inputarg, pgcount);
+		if (ret) {
+			kfree(*inputarg);
+			*inputarg = NULL;
+			return ret;
+		}
+
+		memset(*inputarg, 0x00, PAGE_SIZE);
+	}
+
 	if (hv_root_partition) {
 		outputarg = (void **)this_cpu_ptr(hyperv_pcpu_output_arg);
 		*outputarg = (char *)(*inputarg) + HV_HYP_PAGE_SIZE;
@@ -156,6 +169,7 @@  int hv_common_cpu_die(unsigned int cpu)
 {
 	unsigned long flags;
 	void **inputarg, **outputarg;
+	int pgcount = hv_root_partition ? 2 : 1;
 	void *mem;
 
 	local_irq_save(flags);
@@ -171,7 +185,12 @@  int hv_common_cpu_die(unsigned int cpu)
 
 	local_irq_restore(flags);
 
-	kfree(mem);
+	if (hv_isolation_type_en_snp()) {
+		if (!set_memory_encrypted((unsigned long)mem, pgcount))
+			kfree(mem);
+	} else {
+		kfree(mem);
+	}
 
 	return 0;
 }