diff mbox series

[V3,4/8] xen/virtio: Enable restricted memory access using Xen grant mappings

Message ID 1653944417-17168-5-git-send-email-olekstysh@gmail.com (mailing list archive)
State Superseded
Headers show
Series virtio: Solution to restrict memory access under Xen using xen-grant DMA-mapping layer | expand

Commit Message

Oleksandr Tyshchenko May 30, 2022, 9 p.m. UTC
From: Juergen Gross <jgross@suse.com>

In order to support virtio in Xen guests add a config option XEN_VIRTIO
enabling the user to specify whether in all Xen guests virtio should
be able to access memory via Xen grant mappings only on the host side.

Also set PLATFORM_VIRTIO_RESTRICTED_MEM_ACCESS feature from the guest
initialization code on Arm and x86 if CONFIG_XEN_VIRTIO is enabled.

Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
---
Changes V1 -> V2:
   - new patch, split required changes from commit:
    "[PATCH V1 3/6] xen/virtio: Add option to restrict memory access under Xen"
   - rework according to new platform_has() infrastructure

Changes V2 -> V3:
   - add Stefano's R-b
---
 arch/arm/xen/enlighten.c     |  2 ++
 arch/x86/xen/enlighten_hvm.c |  2 ++
 arch/x86/xen/enlighten_pv.c  |  2 ++
 drivers/xen/Kconfig          | 11 +++++++++++
 include/xen/xen.h            |  8 ++++++++
 5 files changed, 25 insertions(+)

Comments

Oleksandr Tyshchenko June 2, 2022, 12:49 p.m. UTC | #1
On 31.05.22 00:00, Oleksandr Tyshchenko wrote:

Hello all.

> From: Juergen Gross <jgross@suse.com>
>
> In order to support virtio in Xen guests add a config option XEN_VIRTIO
> enabling the user to specify whether in all Xen guests virtio should
> be able to access memory via Xen grant mappings only on the host side.
>
> Also set PLATFORM_VIRTIO_RESTRICTED_MEM_ACCESS feature from the guest
> initialization code on Arm and x86 if CONFIG_XEN_VIRTIO is enabled.
>
> Signed-off-by: Juergen Gross <jgross@suse.com>
> Signed-off-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
> Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
> ---
> Changes V1 -> V2:
>     - new patch, split required changes from commit:
>      "[PATCH V1 3/6] xen/virtio: Add option to restrict memory access under Xen"
>     - rework according to new platform_has() infrastructure
>
> Changes V2 -> V3:
>     - add Stefano's R-b

May I please ask for the ack or comments for x86 side here?



> ---
>   arch/arm/xen/enlighten.c     |  2 ++
>   arch/x86/xen/enlighten_hvm.c |  2 ++
>   arch/x86/xen/enlighten_pv.c  |  2 ++
>   drivers/xen/Kconfig          | 11 +++++++++++
>   include/xen/xen.h            |  8 ++++++++
>   5 files changed, 25 insertions(+)
>
> diff --git a/arch/arm/xen/enlighten.c b/arch/arm/xen/enlighten.c
> index 07eb69f..1f9c3ba 100644
> --- a/arch/arm/xen/enlighten.c
> +++ b/arch/arm/xen/enlighten.c
> @@ -443,6 +443,8 @@ static int __init xen_guest_init(void)
>   	if (!xen_domain())
>   		return 0;
>   
> +	xen_set_restricted_virtio_memory_access();
> +
>   	if (!acpi_disabled)
>   		xen_acpi_guest_init();
>   	else
> diff --git a/arch/x86/xen/enlighten_hvm.c b/arch/x86/xen/enlighten_hvm.c
> index 517a9d8..8b71b1d 100644
> --- a/arch/x86/xen/enlighten_hvm.c
> +++ b/arch/x86/xen/enlighten_hvm.c
> @@ -195,6 +195,8 @@ static void __init xen_hvm_guest_init(void)
>   	if (xen_pv_domain())
>   		return;
>   
> +	xen_set_restricted_virtio_memory_access();
> +
>   	init_hvm_pv_info();
>   
>   	reserve_shared_info();
> diff --git a/arch/x86/xen/enlighten_pv.c b/arch/x86/xen/enlighten_pv.c
> index ca85d14..30d24fe 100644
> --- a/arch/x86/xen/enlighten_pv.c
> +++ b/arch/x86/xen/enlighten_pv.c
> @@ -108,6 +108,8 @@ static DEFINE_PER_CPU(struct tls_descs, shadow_tls_desc);
>   
>   static void __init xen_pv_init_platform(void)
>   {
> +	xen_set_restricted_virtio_memory_access();
> +
>   	populate_extra_pte(fix_to_virt(FIX_PARAVIRT_BOOTMAP));
>   
>   	set_fixmap(FIX_PARAVIRT_BOOTMAP, xen_start_info->shared_info);
> diff --git a/drivers/xen/Kconfig b/drivers/xen/Kconfig
> index 313a9127..a7bd8ce 100644
> --- a/drivers/xen/Kconfig
> +++ b/drivers/xen/Kconfig
> @@ -339,4 +339,15 @@ config XEN_GRANT_DMA_OPS
>   	bool
>   	select DMA_OPS
>   
> +config XEN_VIRTIO
> +	bool "Xen virtio support"
> +	depends on VIRTIO
> +	select XEN_GRANT_DMA_OPS
> +	help
> +	  Enable virtio support for running as Xen guest. Depending on the
> +	  guest type this will require special support on the backend side
> +	  (qemu or kernel, depending on the virtio device types used).
> +
> +	  If in doubt, say n.
> +
>   endmenu
> diff --git a/include/xen/xen.h b/include/xen/xen.h
> index a99bab8..0780a81 100644
> --- a/include/xen/xen.h
> +++ b/include/xen/xen.h
> @@ -52,6 +52,14 @@ bool xen_biovec_phys_mergeable(const struct bio_vec *vec1,
>   extern u64 xen_saved_max_mem_size;
>   #endif
>   
> +#include <linux/platform-feature.h>
> +
> +static inline void xen_set_restricted_virtio_memory_access(void)
> +{
> +	if (IS_ENABLED(CONFIG_XEN_VIRTIO) && xen_domain())
> +		platform_set(PLATFORM_VIRTIO_RESTRICTED_MEM_ACCESS);
> +}
> +
>   #ifdef CONFIG_XEN_UNPOPULATED_ALLOC
>   int xen_alloc_unpopulated_pages(unsigned int nr_pages, struct page **pages);
>   void xen_free_unpopulated_pages(unsigned int nr_pages, struct page **pages);
Boris Ostrovsky June 2, 2022, 7:09 p.m. UTC | #2
On 6/2/22 8:49 AM, Oleksandr wrote:
>
> On 31.05.22 00:00, Oleksandr Tyshchenko wrote:
>
> Hello all.
>
>> From: Juergen Gross <jgross@suse.com>
>>
>> In order to support virtio in Xen guests add a config option XEN_VIRTIO
>> enabling the user to specify whether in all Xen guests virtio should
>> be able to access memory via Xen grant mappings only on the host side.
>>
>> Also set PLATFORM_VIRTIO_RESTRICTED_MEM_ACCESS feature from the guest
>> initialization code on Arm and x86 if CONFIG_XEN_VIRTIO is enabled.
>>
>> Signed-off-by: Juergen Gross <jgross@suse.com>
>> Signed-off-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
>> Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
>> ---
>> Changes V1 -> V2:
>>     - new patch, split required changes from commit:
>>      "[PATCH V1 3/6] xen/virtio: Add option to restrict memory access under Xen"
>>     - rework according to new platform_has() infrastructure
>>
>> Changes V2 -> V3:
>>     - add Stefano's R-b
>
> May I please ask for the ack or comments for x86 side here?
>
>

Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
diff mbox series

Patch

diff --git a/arch/arm/xen/enlighten.c b/arch/arm/xen/enlighten.c
index 07eb69f..1f9c3ba 100644
--- a/arch/arm/xen/enlighten.c
+++ b/arch/arm/xen/enlighten.c
@@ -443,6 +443,8 @@  static int __init xen_guest_init(void)
 	if (!xen_domain())
 		return 0;
 
+	xen_set_restricted_virtio_memory_access();
+
 	if (!acpi_disabled)
 		xen_acpi_guest_init();
 	else
diff --git a/arch/x86/xen/enlighten_hvm.c b/arch/x86/xen/enlighten_hvm.c
index 517a9d8..8b71b1d 100644
--- a/arch/x86/xen/enlighten_hvm.c
+++ b/arch/x86/xen/enlighten_hvm.c
@@ -195,6 +195,8 @@  static void __init xen_hvm_guest_init(void)
 	if (xen_pv_domain())
 		return;
 
+	xen_set_restricted_virtio_memory_access();
+
 	init_hvm_pv_info();
 
 	reserve_shared_info();
diff --git a/arch/x86/xen/enlighten_pv.c b/arch/x86/xen/enlighten_pv.c
index ca85d14..30d24fe 100644
--- a/arch/x86/xen/enlighten_pv.c
+++ b/arch/x86/xen/enlighten_pv.c
@@ -108,6 +108,8 @@  static DEFINE_PER_CPU(struct tls_descs, shadow_tls_desc);
 
 static void __init xen_pv_init_platform(void)
 {
+	xen_set_restricted_virtio_memory_access();
+
 	populate_extra_pte(fix_to_virt(FIX_PARAVIRT_BOOTMAP));
 
 	set_fixmap(FIX_PARAVIRT_BOOTMAP, xen_start_info->shared_info);
diff --git a/drivers/xen/Kconfig b/drivers/xen/Kconfig
index 313a9127..a7bd8ce 100644
--- a/drivers/xen/Kconfig
+++ b/drivers/xen/Kconfig
@@ -339,4 +339,15 @@  config XEN_GRANT_DMA_OPS
 	bool
 	select DMA_OPS
 
+config XEN_VIRTIO
+	bool "Xen virtio support"
+	depends on VIRTIO
+	select XEN_GRANT_DMA_OPS
+	help
+	  Enable virtio support for running as Xen guest. Depending on the
+	  guest type this will require special support on the backend side
+	  (qemu or kernel, depending on the virtio device types used).
+
+	  If in doubt, say n.
+
 endmenu
diff --git a/include/xen/xen.h b/include/xen/xen.h
index a99bab8..0780a81 100644
--- a/include/xen/xen.h
+++ b/include/xen/xen.h
@@ -52,6 +52,14 @@  bool xen_biovec_phys_mergeable(const struct bio_vec *vec1,
 extern u64 xen_saved_max_mem_size;
 #endif
 
+#include <linux/platform-feature.h>
+
+static inline void xen_set_restricted_virtio_memory_access(void)
+{
+	if (IS_ENABLED(CONFIG_XEN_VIRTIO) && xen_domain())
+		platform_set(PLATFORM_VIRTIO_RESTRICTED_MEM_ACCESS);
+}
+
 #ifdef CONFIG_XEN_UNPOPULATED_ALLOC
 int xen_alloc_unpopulated_pages(unsigned int nr_pages, struct page **pages);
 void xen_free_unpopulated_pages(unsigned int nr_pages, struct page **pages);