diff mbox

[v2,13/16] ARM: XEN: Set EFI_PARAVIRT if Xen supports EFI

Message ID 1452840929-19612-14-git-send-email-zhaoshenglong@huawei.com
State New
Headers show

Commit Message

Shannon Zhao Jan. 15, 2016, 6:55 a.m. UTC
From: Shannon Zhao <shannon.zhao@linaro.org>


Check if there is "uefi" node in the DT. If so, set EFI_PARAVIRT flag.

Signed-off-by: Shannon Zhao <shannon.zhao@linaro.org>

---
 arch/arm/xen/enlighten.c | 23 +++++++++++++++++++++++
 arch/arm64/kernel/efi.c  |  5 +++++
 2 files changed, 28 insertions(+)

-- 
2.0.4


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Comments

Mark Rutland Jan. 18, 2016, 10:57 a.m. UTC | #1
On Fri, Jan 15, 2016 at 02:55:26PM +0800, Shannon Zhao wrote:
> From: Shannon Zhao <shannon.zhao@linaro.org>

> 

> Check if there is "uefi" node in the DT. If so, set EFI_PARAVIRT flag.

> 

> Signed-off-by: Shannon Zhao <shannon.zhao@linaro.org>

> ---

>  arch/arm/xen/enlighten.c | 23 +++++++++++++++++++++++

>  arch/arm64/kernel/efi.c  |  5 +++++

>  2 files changed, 28 insertions(+)

> 

> diff --git a/arch/arm/xen/enlighten.c b/arch/arm/xen/enlighten.c

> index 5d0fe68..485e117 100644

> --- a/arch/arm/xen/enlighten.c

> +++ b/arch/arm/xen/enlighten.c

> @@ -31,6 +31,7 @@

>  #include <linux/timekeeping.h>

>  #include <linux/timekeeper_internal.h>

>  #include <linux/acpi.h>

> +#include <linux/efi.h>

>  

>  #include <linux/mm.h>

>  

> @@ -248,6 +249,19 @@ static int __init fdt_find_xen_node(unsigned long node, const char *uname,

>  	return 0;

>  }

>  

> +static int __init fdt_find_uefi_node(unsigned long node, const char *uname,

> +				     int depth, void *data)

> +{

> +	bool *found = data;

> +

> +	if (depth != 2 || strcmp(uname, "uefi") != 0)

> +		return 0;

> +

> +	*found = true;

> +

> +	return 1;

> +}


I don't like this. What if we had to add a uefi node in the !Xen case
for some reason?

You want to look for /hypervisor/uefi, specifically when the hypervisor
compatible contains "xen,xen".

It would be better to find the "/hypervisor" node, checking for the
compatible string, then walk within that in the Xen-specific init
routine.

> +

>  /*

>   * see Documentation/devicetree/bindings/arm/xen.txt for the

>   * documentation of the Xen Device Tree format.

> @@ -255,6 +269,8 @@ static int __init fdt_find_xen_node(unsigned long node, const char *uname,

>  #define GRANT_TABLE_PHYSADDR 0

>  void __init xen_early_init(void)

>  {

> +	bool uefi_found = false;

> +

>  	of_scan_flat_dt(fdt_find_xen_node, NULL);

>  	if (!xen_node.found) {

>  		pr_debug("No Xen support\n");

> @@ -279,6 +295,13 @@ void __init xen_early_init(void)

>  

>  	if (!console_set_on_cmdline && !xen_initial_domain())

>  		add_preferred_console("hvc", 0, NULL);

> +

> +	if (IS_ENABLED(CONFIG_XEN_EFI)) {

> +		/* Check if Xen support UEFI */

> +		of_scan_flat_dt(fdt_find_uefi_node, &uefi_found);

> +		if (uefi_found)

> +			set_bit(EFI_PARAVIRT, &efi.flags);

> +	}

>  }


This alone is insufficient given that we haven't parsed the rest of the
/hypervisor/uefi properties. Is the kernel resilient such that this
patch alone will not result in a panic?

I think it would be best for this to be in the same patch as the rest of
the hypervisor UEFI property parsing, being unified with that.

Mark.

>  static int __init xen_guest_init(void)

> diff --git a/arch/arm64/kernel/efi.c b/arch/arm64/kernel/efi.c

> index 4eeb171..16c6b72 100644

> --- a/arch/arm64/kernel/efi.c

> +++ b/arch/arm64/kernel/efi.c

> @@ -288,6 +288,11 @@ static int __init arm64_enable_runtime_services(void)

>  		return 0;

>  	}

>  

> +	if (efi_enabled(EFI_PARAVIRT)) {

> +		pr_info("EFI runtime services access via paravirt.\n");

> +		return -1;

> +	}

> +

>  	pr_info("Remapping and enabling EFI services.\n");

>  

>  	mapsize = memmap.map_end - memmap.map;

> -- 

> 2.0.4

> 

> 

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> 

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diff mbox

Patch

diff --git a/arch/arm/xen/enlighten.c b/arch/arm/xen/enlighten.c
index 5d0fe68..485e117 100644
--- a/arch/arm/xen/enlighten.c
+++ b/arch/arm/xen/enlighten.c
@@ -31,6 +31,7 @@ 
 #include <linux/timekeeping.h>
 #include <linux/timekeeper_internal.h>
 #include <linux/acpi.h>
+#include <linux/efi.h>
 
 #include <linux/mm.h>
 
@@ -248,6 +249,19 @@  static int __init fdt_find_xen_node(unsigned long node, const char *uname,
 	return 0;
 }
 
+static int __init fdt_find_uefi_node(unsigned long node, const char *uname,
+				     int depth, void *data)
+{
+	bool *found = data;
+
+	if (depth != 2 || strcmp(uname, "uefi") != 0)
+		return 0;
+
+	*found = true;
+
+	return 1;
+}
+
 /*
  * see Documentation/devicetree/bindings/arm/xen.txt for the
  * documentation of the Xen Device Tree format.
@@ -255,6 +269,8 @@  static int __init fdt_find_xen_node(unsigned long node, const char *uname,
 #define GRANT_TABLE_PHYSADDR 0
 void __init xen_early_init(void)
 {
+	bool uefi_found = false;
+
 	of_scan_flat_dt(fdt_find_xen_node, NULL);
 	if (!xen_node.found) {
 		pr_debug("No Xen support\n");
@@ -279,6 +295,13 @@  void __init xen_early_init(void)
 
 	if (!console_set_on_cmdline && !xen_initial_domain())
 		add_preferred_console("hvc", 0, NULL);
+
+	if (IS_ENABLED(CONFIG_XEN_EFI)) {
+		/* Check if Xen support UEFI */
+		of_scan_flat_dt(fdt_find_uefi_node, &uefi_found);
+		if (uefi_found)
+			set_bit(EFI_PARAVIRT, &efi.flags);
+	}
 }
 
 static int __init xen_guest_init(void)
diff --git a/arch/arm64/kernel/efi.c b/arch/arm64/kernel/efi.c
index 4eeb171..16c6b72 100644
--- a/arch/arm64/kernel/efi.c
+++ b/arch/arm64/kernel/efi.c
@@ -288,6 +288,11 @@  static int __init arm64_enable_runtime_services(void)
 		return 0;
 	}
 
+	if (efi_enabled(EFI_PARAVIRT)) {
+		pr_info("EFI runtime services access via paravirt.\n");
+		return -1;
+	}
+
 	pr_info("Remapping and enabling EFI services.\n");
 
 	mapsize = memmap.map_end - memmap.map;