thr3ads.net - Xen devel - [PATCH v3 0/6] Introduce Xen support to ARM64 [Jun 2013]

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Stefano Stabellini

2013-Jun-05 12:14 UTC

[PATCH v3 0/6] Introduce Xen support to ARM64

Hi all,
this patch series introduces Xen support to arch/arm64.

As you can see from the following patches, there is very little arm64
specific code here, basically only one assembly file
(arch/arm64/xen/hypercall.S).

Everything else is common with Xen for ARMv7, in particular the code
under arch/arm/xen (enlighten.c and the stubs in grant-table.c) and most
of the header files under arch/arm/include/asm/xen (hypercall.h,
hypervisor.h, interface.h, page.h) can be reused as-is.



Changes in v3:
- fix comment in hypercall.S to reflect the actual calling convention;
- add a patch to update the MAINTAINERS file.



Stefano Stabellini (6):
      arm/xen: define xen_remap as ioremap_cached
      arm64/xen: introduce asm/xen header files on arm64
      arm64/xen: implement ioremap_cached on arm64
      arm64/xen: use XEN_IO_PROTO_ABI_ARM on ARM64
      arm64/xen: introduce CONFIG_XEN and hypercall.S on ARM64
      MAINTAINERS: add myself as arm64/xen maintainer

 MAINTAINERS                             |    7 ++
 arch/arm/include/asm/xen/page.h         |    3 +-
 arch/arm64/Kconfig                      |   10 +++
 arch/arm64/Makefile                     |    1 +
 arch/arm64/include/asm/hypervisor.h     |    6 ++
 arch/arm64/include/asm/io.h             |    2 +
 arch/arm64/include/asm/sync_bitops.h    |   26 +++++++++
 arch/arm64/include/asm/xen/events.h     |   21 +++++++
 arch/arm64/include/asm/xen/hypercall.h  |    1 +
 arch/arm64/include/asm/xen/hypervisor.h |    1 +
 arch/arm64/include/asm/xen/interface.h  |    1 +
 arch/arm64/include/asm/xen/page.h       |    1 +
 arch/arm64/xen/Makefile                 |    2 +
 arch/arm64/xen/hypercall.S              |   92 +++++++++++++++++++++++++++++++
 include/xen/interface/io/protocols.h    |    2 +-
 15 files changed, 173 insertions(+), 3 deletions(-)
 create mode 100644 arch/arm64/include/asm/hypervisor.h
 create mode 100644 arch/arm64/include/asm/sync_bitops.h
 create mode 100644 arch/arm64/include/asm/xen/events.h
 create mode 100644 arch/arm64/include/asm/xen/hypercall.h
 create mode 100644 arch/arm64/include/asm/xen/hypervisor.h
 create mode 100644 arch/arm64/include/asm/xen/interface.h
 create mode 100644 arch/arm64/include/asm/xen/page.h
 create mode 100644 arch/arm64/xen/Makefile
 create mode 100644 arch/arm64/xen/hypercall.S


git://git.kernel.org/pub/scm/linux/kernel/git/sstabellini/xen.git xen-arm64-3


- Stefano

Stefano Stabellini

2013-Jun-05 12:15 UTC

head link

[PATCH v3 1/6] arm/xen: define xen_remap as ioremap_cached

Define xen_remap as ioremap_cache (MT_MEMORY and MT_DEVICE_CACHED end up
having the same AttrIndx encoding).

Remove include asm/mach/map.h, not unneeded.

Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
---
 arch/arm/include/asm/xen/page.h |    3 +--
 1 files changed, 1 insertions(+), 2 deletions(-)

diff --git a/arch/arm/include/asm/xen/page.h b/arch/arm/include/asm/xen/page.h
index 30cdacb..359a7b5 100644
--- a/arch/arm/include/asm/xen/page.h
+++ b/arch/arm/include/asm/xen/page.h
@@ -1,7 +1,6 @@
 #ifndef _ASM_ARM_XEN_PAGE_H
 #define _ASM_ARM_XEN_PAGE_H
 
-#include <asm/mach/map.h>
 #include <asm/page.h>
 #include <asm/pgtable.h>
 
@@ -88,6 +87,6 @@ static inline bool set_phys_to_machine(unsigned long pfn,
unsigned long mfn)
 	return __set_phys_to_machine(pfn, mfn);
 }
 
-#define xen_remap(cookie, size) __arm_ioremap((cookie), (size), MT_MEMORY);
+#define xen_remap(cookie, size) ioremap_cached((cookie), (size));
 
 #endif /* _ASM_ARM_XEN_PAGE_H */
-- 
1.7.2.5

Stefano Stabellini

2013-Jun-05 12:15 UTC

head link

[PATCH v3 2/6] arm64/xen: introduce asm/xen header files on arm64

asm/xen/hypercall.h, asm/xen/hypervisor.h, asm/xen/interface.h and
asm/xen/page.h are identical so to avoid code duplication we are just
including the original arm header files here.

asm/xen/events.h is slightly different, so introduce a different file
here (use xchg to implement xchg_xen_ulong and pass regs->pstate to
raw_irqs_disabled_flags).

Also introduce asm/hypervisor.h and asm/sync_bitops.h.

Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>

Change in v2:
- add all the required headers in this patch, by including the original
  arch/arm headers when possible to avoid code duplication;
- use xchg to implement xchg_xen_ulong.
---
 arch/arm64/include/asm/hypervisor.h     |    6 ++++++
 arch/arm64/include/asm/sync_bitops.h    |   26 ++++++++++++++++++++++++++
 arch/arm64/include/asm/xen/events.h     |   21 +++++++++++++++++++++
 arch/arm64/include/asm/xen/hypercall.h  |    1 +
 arch/arm64/include/asm/xen/hypervisor.h |    1 +
 arch/arm64/include/asm/xen/interface.h  |    1 +
 arch/arm64/include/asm/xen/page.h       |    1 +
 7 files changed, 57 insertions(+), 0 deletions(-)
 create mode 100644 arch/arm64/include/asm/hypervisor.h
 create mode 100644 arch/arm64/include/asm/sync_bitops.h
 create mode 100644 arch/arm64/include/asm/xen/events.h
 create mode 100644 arch/arm64/include/asm/xen/hypercall.h
 create mode 100644 arch/arm64/include/asm/xen/hypervisor.h
 create mode 100644 arch/arm64/include/asm/xen/interface.h
 create mode 100644 arch/arm64/include/asm/xen/page.h

diff --git a/arch/arm64/include/asm/hypervisor.h
b/arch/arm64/include/asm/hypervisor.h
new file mode 100644
index 0000000..d2c7904
--- /dev/null
+++ b/arch/arm64/include/asm/hypervisor.h
@@ -0,0 +1,6 @@
+#ifndef _ASM_ARM64_HYPERVISOR_H
+#define _ASM_ARM64_HYPERVISOR_H
+
+#include <asm/xen/hypervisor.h>
+
+#endif
diff --git a/arch/arm64/include/asm/sync_bitops.h
b/arch/arm64/include/asm/sync_bitops.h
new file mode 100644
index 0000000..8da0bf4
--- /dev/null
+++ b/arch/arm64/include/asm/sync_bitops.h
@@ -0,0 +1,26 @@
+#ifndef __ASM_SYNC_BITOPS_H__
+#define __ASM_SYNC_BITOPS_H__
+
+#include <asm/bitops.h>
+#include <asm/cmpxchg.h>
+
+/* sync_bitops functions are equivalent to the SMP implementation of the
+ * original functions, independently from CONFIG_SMP being defined.
+ *
+ * We need them because _set_bit etc are not SMP safe if !CONFIG_SMP. But
+ * under Xen you might be communicating with a completely external entity
+ * who might be on another CPU (e.g. two uniprocessor guests communicating
+ * via event channels and grant tables). So we need a variant of the bit
+ * ops which are SMP safe even on a UP kernel.
+ */
+
+#define sync_set_bit(nr, p)            set_bit(nr, p)
+#define sync_clear_bit(nr, p)          clear_bit(nr, p)
+#define sync_change_bit(nr, p)         change_bit(nr, p)
+#define sync_test_and_set_bit(nr, p)   test_and_set_bit(nr, p)
+#define sync_test_and_clear_bit(nr, p) test_and_clear_bit(nr, p)
+#define sync_test_and_change_bit(nr, p)        test_and_change_bit(nr, p)
+#define sync_test_bit(nr, addr)                test_bit(nr, addr)
+#define sync_cmpxchg                   cmpxchg
+
+#endif
diff --git a/arch/arm64/include/asm/xen/events.h
b/arch/arm64/include/asm/xen/events.h
new file mode 100644
index 0000000..8655321
--- /dev/null
+++ b/arch/arm64/include/asm/xen/events.h
@@ -0,0 +1,21 @@
+#ifndef _ASM_ARM64_XEN_EVENTS_H
+#define _ASM_ARM64_XEN_EVENTS_H
+
+#include <asm/ptrace.h>
+#include <asm/atomic.h>
+
+enum ipi_vector {
+	XEN_PLACEHOLDER_VECTOR,
+
+	/* Xen IPIs go here */
+	XEN_NR_IPIS,
+};
+
+static inline int xen_irqs_disabled(struct pt_regs *regs)
+{
+	return raw_irqs_disabled_flags((unsigned long) regs->pstate);
+}
+
+#define xchg_xen_ulong(ptr, val) xchg((ptr), (val))
+
+#endif /* _ASM_ARM64_XEN_EVENTS_H */
diff --git a/arch/arm64/include/asm/xen/hypercall.h
b/arch/arm64/include/asm/xen/hypercall.h
new file mode 100644
index 0000000..74b0c42
--- /dev/null
+++ b/arch/arm64/include/asm/xen/hypercall.h
@@ -0,0 +1 @@
+#include <../../arm/include/asm/xen/hypercall.h>
diff --git a/arch/arm64/include/asm/xen/hypervisor.h
b/arch/arm64/include/asm/xen/hypervisor.h
new file mode 100644
index 0000000..f263da8
--- /dev/null
+++ b/arch/arm64/include/asm/xen/hypervisor.h
@@ -0,0 +1 @@
+#include <../../arm/include/asm/xen/hypervisor.h>
diff --git a/arch/arm64/include/asm/xen/interface.h
b/arch/arm64/include/asm/xen/interface.h
new file mode 100644
index 0000000..44457ae
--- /dev/null
+++ b/arch/arm64/include/asm/xen/interface.h
@@ -0,0 +1 @@
+#include <../../arm/include/asm/xen/interface.h>
diff --git a/arch/arm64/include/asm/xen/page.h
b/arch/arm64/include/asm/xen/page.h
new file mode 100644
index 0000000..bed87ec
--- /dev/null
+++ b/arch/arm64/include/asm/xen/page.h
@@ -0,0 +1 @@
+#include <../../arm/include/asm/xen/page.h>
-- 
1.7.2.5

Stefano Stabellini

2013-Jun-05 12:15 UTC

head link

[PATCH v3 3/6] arm64/xen: implement ioremap_cached on arm64

Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
---
 arch/arm64/include/asm/io.h |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)

diff --git a/arch/arm64/include/asm/io.h b/arch/arm64/include/asm/io.h
index 2e12258..1d12f89 100644
--- a/arch/arm64/include/asm/io.h
+++ b/arch/arm64/include/asm/io.h
@@ -228,10 +228,12 @@ extern void __iounmap(volatile void __iomem *addr);
 #define PROT_DEFAULT		(PTE_TYPE_PAGE | PTE_AF | PTE_DIRTY)
 #define PROT_DEVICE_nGnRE	(PROT_DEFAULT | PTE_PXN | PTE_UXN |
PTE_ATTRINDX(MT_DEVICE_nGnRE))
 #define PROT_NORMAL_NC		(PROT_DEFAULT | PTE_ATTRINDX(MT_NORMAL_NC))
+#define PROT_NORMAL		(PROT_DEFAULT | PTE_ATTRINDX(MT_NORMAL))
 
 #define ioremap(addr, size)		__ioremap((addr), (size),
__pgprot(PROT_DEVICE_nGnRE))
 #define ioremap_nocache(addr, size)	__ioremap((addr), (size),
__pgprot(PROT_DEVICE_nGnRE))
 #define ioremap_wc(addr, size)		__ioremap((addr), (size),
__pgprot(PROT_NORMAL_NC))
+#define ioremap_cached(addr, size)	__ioremap((addr), (size),
__pgprot(PROT_NORMAL))
 #define iounmap				__iounmap
 
 #define PROT_SECT_DEFAULT	(PMD_TYPE_SECT | PMD_SECT_AF)
-- 
1.7.2.5

Stefano Stabellini

2013-Jun-05 12:15 UTC

head link

[PATCH v3 4/6] arm64/xen: use XEN_IO_PROTO_ABI_ARM on ARM64

Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
---
 include/xen/interface/io/protocols.h |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/include/xen/interface/io/protocols.h
b/include/xen/interface/io/protocols.h
index 0eafaf2..056744b 100644
--- a/include/xen/interface/io/protocols.h
+++ b/include/xen/interface/io/protocols.h
@@ -15,7 +15,7 @@
 # define XEN_IO_PROTO_ABI_NATIVE XEN_IO_PROTO_ABI_IA64
 #elif defined(__powerpc64__)
 # define XEN_IO_PROTO_ABI_NATIVE XEN_IO_PROTO_ABI_POWERPC64
-#elif defined(__arm__)
+#elif defined(__arm__) || defined(__aarch64__)
 # define XEN_IO_PROTO_ABI_NATIVE XEN_IO_PROTO_ABI_ARM
 #else
 # error arch fixup needed here
-- 
1.7.2.5

Stefano Stabellini

2013-Jun-05 12:15 UTC

head link

[PATCH v3 5/6] arm64/xen: introduce CONFIG_XEN and hypercall.S on ARM64

Introduce CONFIG_XEN and the implementation of hypercall.S (that is
the only ARMv8 specific code in Xen support for ARM).

Compile enlighten.c and grant_table.c from arch/arm.

Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>

Changes in v2:
- remove depends on !GENERIC_ATOMIC64;
- compile enlighten.c and grant_table.c from arch/arm directly;
- fix the privcmd implementation: according to the aarch64 procedure
call ABI the first 7 parameters are passed on registers so we don''t
need
to push/pop anything.

Changes in v3:
- update comment to reflect the actual hypercall calling convention.
---
 arch/arm64/Kconfig         |   10 +++++
 arch/arm64/Makefile        |    1 +
 arch/arm64/xen/Makefile    |    2 +
 arch/arm64/xen/hypercall.S |   92 ++++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 105 insertions(+), 0 deletions(-)
 create mode 100644 arch/arm64/xen/Makefile
 create mode 100644 arch/arm64/xen/hypercall.S

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 56b3f6d..b5d6ada 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -182,6 +182,16 @@ config HW_PERF_EVENTS
 
 source "mm/Kconfig"
 
+config XEN_DOM0
+	def_bool y
+	depends on XEN
+
+config XEN
+	bool "Xen guest support on ARM64 (EXPERIMENTAL)"
+	depends on ARM64 && OF
+	help
+	  Say Y if you want to run Linux in a Virtual Machine on Xen on ARM64.
+
 endmenu
 
 menu "Boot options"
diff --git a/arch/arm64/Makefile b/arch/arm64/Makefile
index c95c5cb..79dd13d 100644
--- a/arch/arm64/Makefile
+++ b/arch/arm64/Makefile
@@ -37,6 +37,7 @@ TEXT_OFFSET := 0x00080000
 export	TEXT_OFFSET GZFLAGS
 
 core-y		+= arch/arm64/kernel/ arch/arm64/mm/
+core-$(CONFIG_XEN)		+= arch/arm64/xen/
 libs-y		:= arch/arm64/lib/ $(libs-y)
 libs-y		+= $(LIBGCC)
 
diff --git a/arch/arm64/xen/Makefile b/arch/arm64/xen/Makefile
new file mode 100644
index 0000000..be24040
--- /dev/null
+++ b/arch/arm64/xen/Makefile
@@ -0,0 +1,2 @@
+xen-arm-y	+= $(addprefix ../../arm/xen/, enlighten.o grant-table.o)
+obj-y		:= xen-arm.o hypercall.o
diff --git a/arch/arm64/xen/hypercall.S b/arch/arm64/xen/hypercall.S
new file mode 100644
index 0000000..71d1a49
--- /dev/null
+++ b/arch/arm64/xen/hypercall.S
@@ -0,0 +1,92 @@
+/******************************************************************************
+ * hypercall.S
+ *
+ * Xen hypercall wrappers
+ *
+ * Stefano Stabellini <stefano.stabellini@eu.citrix.com>, Citrix, 2012
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License version 2
+ * as published by the Free Software Foundation; or, when distributed
+ * separately from the Linux kernel or incorporated into other
+ * software packages, subject to the following license:
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this source file (the "Software"), to deal in the Software
without
+ * restriction, including without limitation the rights to use, copy, modify,
+ * merge, publish, distribute, sublicense, and/or sell copies of the Software,
+ * and to permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+
+/*
+ * The Xen hypercall calling convention is very similar to the procedure
+ * call standard for the ARM 64-bit architecture: the first parameter is
+ * passed in x0, the second in x1, the third in x2, the fourth in x3 and
+ * the fifth in x4.
+ *
+ * The hypercall number is passed in x16.
+ *
+ * The return value is in x0.
+ *
+ * The hvc ISS is required to be 0xEA1, that is the Xen specific ARM
+ * hypercall tag.
+ *
+ * Parameter structs passed to hypercalls are laid out according to
+ * the ARM 64-bit EABI standard.
+ */
+
+#include <linux/linkage.h>
+#include <asm/assembler.h>
+#include <xen/interface/xen.h>
+
+
+#define XEN_IMM 0xEA1
+
+#define HYPERCALL_SIMPLE(hypercall)		\
+ENTRY(HYPERVISOR_##hypercall)			\
+	mov x16, #__HYPERVISOR_##hypercall;	\
+	hvc XEN_IMM;						\
+	ret;								\
+ENDPROC(HYPERVISOR_##hypercall)
+
+#define HYPERCALL0 HYPERCALL_SIMPLE
+#define HYPERCALL1 HYPERCALL_SIMPLE
+#define HYPERCALL2 HYPERCALL_SIMPLE
+#define HYPERCALL3 HYPERCALL_SIMPLE
+#define HYPERCALL4 HYPERCALL_SIMPLE
+#define HYPERCALL5 HYPERCALL_SIMPLE
+
+                .text
+
+HYPERCALL2(xen_version);
+HYPERCALL3(console_io);
+HYPERCALL3(grant_table_op);
+HYPERCALL2(sched_op);
+HYPERCALL2(event_channel_op);
+HYPERCALL2(hvm_op);
+HYPERCALL2(memory_op);
+HYPERCALL2(physdev_op);
+HYPERCALL3(vcpu_op);
+
+ENTRY(privcmd_call)
+	mov x16, x0
+	mov x0, x1
+	mov x1, x2
+	mov x2, x3
+	mov x3, x4
+	mov x4, x5
+	hvc XEN_IMM
+	ret
+ENDPROC(privcmd_call);
-- 
1.7.2.5

Stefano Stabellini

2013-Jun-05 12:15 UTC

head link

[PATCH v3 6/6] MAINTAINERS: add myself as arm64/xen maintainer

Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
---
 MAINTAINERS |    7 +++++++
 1 files changed, 7 insertions(+), 0 deletions(-)

diff --git a/MAINTAINERS b/MAINTAINERS
index fd3a495..95a6a51 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -9096,6 +9096,13 @@ S:	Supported
 F:	arch/arm/xen/
 F:	arch/arm/include/asm/xen/
 
+XEN HYPERVISOR ARM64
+M:	Stefano Stabellini <stefano.stabellini@eu.citrix.com>
+L:	xen-devel@lists.xensource.com (moderated for non-subscribers)
+S:	Supported
+F:	arch/arm64/xen/
+F:	arch/arm64/include/asm/xen/
+
 XEN NETWORK BACKEND DRIVER
 M:	Ian Campbell <ian.campbell@citrix.com>
 L:	xen-devel@lists.xensource.com (moderated for non-subscribers)
-- 
1.7.2.5

Ian Campbell

2013-Jun-05 12:23 UTC

head link

Re: [PATCH v3 5/6] arm64/xen: introduce CONFIG_XEN and hypercall.S on ARM64

On Wed, 2013-06-05 at 13:15 +0100, Stefano Stabellini
wrote:> Introduce CONFIG_XEN and the implementation of hypercall.S (that is
> the only ARMv8 specific code in Xen support for ARM).
> 
> Compile enlighten.c and grant_table.c from arch/arm.
> 
> Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
> [....]
> +#define HYPERCALL_SIMPLE(hypercall)		\
> +ENTRY(HYPERVISOR_##hypercall)			\
> +	mov x16, #__HYPERVISOR_##hypercall;	\
> +	hvc XEN_IMM;						\
> +	ret;								\
Not sure if this is corruption due to whitespace/email etc but it''d be
nice to align those \''s.

Ian.

Ian Campbell

2013-Jun-05 12:23 UTC

head link

Re: [PATCH v3 6/6] MAINTAINERS: add myself as arm64/xen maintainer

On Wed, 2013-06-05 at 13:15 +0100, Stefano Stabellini
wrote:> Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
> ---
>  MAINTAINERS |    7 +++++++
>  1 files changed, 7 insertions(+), 0 deletions(-)
> 
> diff --git a/MAINTAINERS b/MAINTAINERS
> index fd3a495..95a6a51 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -9096,6 +9096,13 @@ S:	Supported
>  F:	arch/arm/xen/
>  F:	arch/arm/include/asm/xen/
>  
> +XEN HYPERVISOR ARM64
> +M:	Stefano Stabellini <stefano.stabellini@eu.citrix.com>
> +L:	xen-devel@lists.xensource.com (moderated for non-subscribers)
> +S:	Supported
> +F:	arch/arm64/xen/
> +F:	arch/arm64/include/asm/xen/
> +
>  XEN NETWORK BACKEND DRIVER
>  M:	Ian Campbell <ian.campbell@citrix.com>
>  L:	xen-devel@lists.xensource.com (moderated for non-subscribers)

Stefano Stabellini

2013-Jun-05 12:38 UTC

head link

Re: [PATCH v3 5/6] arm64/xen: introduce CONFIG_XEN and hypercall.S on ARM64

On Wed, 5 Jun 2013, Ian Campbell wrote:> On Wed, 2013-06-05 at 13:15 +0100, Stefano Stabellini wrote:
> > Introduce CONFIG_XEN and the implementation of hypercall.S (that is
> > the only ARMv8 specific code in Xen support for ARM).
> > 
> > Compile enlighten.c and grant_table.c from arch/arm.
> > 
> > Signed-off-by: Stefano Stabellini
<stefano.stabellini@eu.citrix.com>
> 
> Acked-by: Ian Campbell <ian.campbell@citrix.com>
> 
> > [....]
> > +#define HYPERCALL_SIMPLE(hypercall)		\
> > +ENTRY(HYPERVISOR_##hypercall)			\
> > +	mov x16, #__HYPERVISOR_##hypercall;	\
> > +	hvc XEN_IMM;						\
> > +	ret;								\
> 
> Not sure if this is corruption due to whitespace/email etc but
it''d be
> nice to align those \''s.
They are aligned with ts=4, misaligned with ts=8 (ts is vim terminology
for "how many spaces a tab equals to") :-/

Given that according to Linux coding style tabs are 8 characters, I''ll
fix the indentation.

Arnd Bergmann

2013-Jun-05 12:44 UTC

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Re: [PATCH v3 5/6] arm64/xen: introduce CONFIG_XEN and hypercall.S on ARM64

On Wednesday 05 June 2013 13:15:29 Stefano Stabellini
wrote:> diff --git a/arch/arm64/Makefile b/arch/arm64/Makefile
> index c95c5cb..79dd13d 100644
> --- a/arch/arm64/Makefile
> +++ b/arch/arm64/Makefile
> @@ -37,6 +37,7 @@ TEXT_OFFSET := 0x00080000
>  export TEXT_OFFSET GZFLAGS
>  
>  core-y         += arch/arm64/kernel/ arch/arm64/mm/
> +core-$(CONFIG_XEN)             += arch/arm64/xen/
>  libs-y         := arch/arm64/lib/ $(libs-y)
>  libs-y         += $(LIBGCC)
>  
> diff --git a/arch/arm64/xen/Makefile b/arch/arm64/xen/Makefile
> new file mode 100644
> index 0000000..be24040
> --- /dev/null
> +++ b/arch/arm64/xen/Makefile
> @@ -0,0 +1,2 @@
> +xen-arm-y      += $(addprefix ../../arm/xen/, enlighten.o grant-table.o)
> +obj-y          := xen-arm.o hypercall.o
I think it would be nicer to redirect the entire directory, not just
the enlighten.o and grant-table.o files. You could do in arch/arm64/Makefile:

core-(CONFIG_XEN) += arch/arm/xen/

That leaves a small difference in hypercall.o, which I think you can
handle with an #ifdef.

I believe the reason why KVM does the more elaborate variant is that
they want to be able to build their code as a loadable module that
also includes code from virt/kvm, which you don''t need.

	Arnd

Will Deacon

2013-Jun-05 12:50 UTC

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Re: [PATCH v3 5/6] arm64/xen: introduce CONFIG_XEN and hypercall.S on ARM64

On Wed, Jun 05, 2013 at 01:44:55PM +0100, Arnd Bergmann
wrote:> On Wednesday 05 June 2013 13:15:29 Stefano Stabellini wrote:
> > diff --git a/arch/arm64/Makefile b/arch/arm64/Makefile
> > index c95c5cb..79dd13d 100644
> > --- a/arch/arm64/Makefile
> > +++ b/arch/arm64/Makefile
> > @@ -37,6 +37,7 @@ TEXT_OFFSET := 0x00080000
> >  export TEXT_OFFSET GZFLAGS
> >  
> >  core-y         += arch/arm64/kernel/ arch/arm64/mm/
> > +core-$(CONFIG_XEN)             += arch/arm64/xen/
> >  libs-y         := arch/arm64/lib/ $(libs-y)
> >  libs-y         += $(LIBGCC)
> >  
> > diff --git a/arch/arm64/xen/Makefile b/arch/arm64/xen/Makefile
> > new file mode 100644
> > index 0000000..be24040
> > --- /dev/null
> > +++ b/arch/arm64/xen/Makefile
> > @@ -0,0 +1,2 @@
> > +xen-arm-y      += $(addprefix ../../arm/xen/, enlighten.o
grant-table.o)
> > +obj-y          := xen-arm.o hypercall.o
> 
> I think it would be nicer to redirect the entire directory, not just
> the enlighten.o and grant-table.o files. You could do in
arch/arm64/Makefile:
> 
> core-(CONFIG_XEN) += arch/arm/xen/
> 
> That leaves a small difference in hypercall.o, which I think you can
> handle with an #ifdef.
> 
> I believe the reason why KVM does the more elaborate variant is that
> they want to be able to build their code as a loadable module that
> also includes code from virt/kvm, which you don''t need.
I thought we scrapped the idea of KVM as a loadable module on ARM, mainly
due to the complexities with retrospective initialisation of HYP mode/EL2?

Will

Stefano Stabellini

2013-Jun-05 13:04 UTC

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Re: [PATCH v3 5/6] arm64/xen: introduce CONFIG_XEN and hypercall.S on ARM64

On Wed, 5 Jun 2013, Arnd Bergmann wrote:> On Wednesday 05 June 2013 13:15:29 Stefano Stabellini wrote:
> > diff --git a/arch/arm64/Makefile b/arch/arm64/Makefile
> > index c95c5cb..79dd13d 100644
> > --- a/arch/arm64/Makefile
> > +++ b/arch/arm64/Makefile
> > @@ -37,6 +37,7 @@ TEXT_OFFSET := 0x00080000
> >  export TEXT_OFFSET GZFLAGS
> >  
> >  core-y         += arch/arm64/kernel/ arch/arm64/mm/
> > +core-$(CONFIG_XEN)             += arch/arm64/xen/
> >  libs-y         := arch/arm64/lib/ $(libs-y)
> >  libs-y         += $(LIBGCC)
> >  
> > diff --git a/arch/arm64/xen/Makefile b/arch/arm64/xen/Makefile
> > new file mode 100644
> > index 0000000..be24040
> > --- /dev/null
> > +++ b/arch/arm64/xen/Makefile
> > @@ -0,0 +1,2 @@
> > +xen-arm-y      += $(addprefix ../../arm/xen/, enlighten.o
grant-table.o)
> > +obj-y          := xen-arm.o hypercall.o
> 
> I think it would be nicer to redirect the entire directory, not just
> the enlighten.o and grant-table.o files. You could do in
arch/arm64/Makefile:
> 
> core-(CONFIG_XEN) += arch/arm/xen/
> 
> That leaves a small difference in hypercall.o, which I think you can
> handle with an #ifdef.
That is nicer.

The implementation of hypercall.S is significantly different between
arm32 and arm64, so hypercall.S is going to be harder to read.
However hypercall.S is just one file and it''s not going to grow much,
while we might have many more C source files in common between the two
architecures, so I think that your approach is going to be cleaner in
the long term.

I''ll make the change.

Konrad Rzeszutek Wilk

2013-Jun-05 14:27 UTC

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Re: [PATCH v3 6/6] MAINTAINERS: add myself as arm64/xen maintainer

On Wed, Jun 05, 2013 at 01:15:30PM +0100, Stefano Stabellini
wrote:> Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Acked-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

(not sure if that is needed, but I am more than happy to have Stefano be
the Xen-ARM guy and I can be the Xen-generic-and-x86 guy).
> ---
>  MAINTAINERS |    7 +++++++
>  1 files changed, 7 insertions(+), 0 deletions(-)
> 
> diff --git a/MAINTAINERS b/MAINTAINERS
> index fd3a495..95a6a51 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -9096,6 +9096,13 @@ S:	Supported
>  F:	arch/arm/xen/
>  F:	arch/arm/include/asm/xen/
>  
> +XEN HYPERVISOR ARM64
> +M:	Stefano Stabellini <stefano.stabellini@eu.citrix.com>
> +L:	xen-devel@lists.xensource.com (moderated for non-subscribers)
> +S:	Supported
> +F:	arch/arm64/xen/
> +F:	arch/arm64/include/asm/xen/
> +
>  XEN NETWORK BACKEND DRIVER
>  M:	Ian Campbell <ian.campbell@citrix.com>
>  L:	xen-devel@lists.xensource.com (moderated for non-subscribers)
> -- 
> 1.7.2.5
>

Christopher Covington

2013-Jun-05 14:43 UTC

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Re: [PATCH v3 5/6] arm64/xen: introduce CONFIG_XEN and hypercall.S on ARM64

Hi Will,

On 06/05/2013 08:50 AM, Will Deacon wrote:> On Wed, Jun 05, 2013 at 01:44:55PM +0100, Arnd Bergmann wrote:
>> On Wednesday 05 June 2013 13:15:29 Stefano Stabellini wrote:
>>> diff --git a/arch/arm64/Makefile b/arch/arm64/Makefile
>>> index c95c5cb..79dd13d 100644
>>> --- a/arch/arm64/Makefile
>>> +++ b/arch/arm64/Makefile
>>> @@ -37,6 +37,7 @@ TEXT_OFFSET := 0x00080000
>>>  export TEXT_OFFSET GZFLAGS
>>>  
>>>  core-y         += arch/arm64/kernel/ arch/arm64/mm/
>>> +core-$(CONFIG_XEN)             += arch/arm64/xen/
>>>  libs-y         := arch/arm64/lib/ $(libs-y)
>>>  libs-y         += $(LIBGCC)
>>>  
>>> diff --git a/arch/arm64/xen/Makefile b/arch/arm64/xen/Makefile
>>> new file mode 100644
>>> index 0000000..be24040
>>> --- /dev/null
>>> +++ b/arch/arm64/xen/Makefile
>>> @@ -0,0 +1,2 @@
>>> +xen-arm-y      += $(addprefix ../../arm/xen/, enlighten.o
grant-table.o)
>>> +obj-y          := xen-arm.o hypercall.o
>>
>> I think it would be nicer to redirect the entire directory, not just
>> the enlighten.o and grant-table.o files. You could do in
arch/arm64/Makefile:
>>
>> core-(CONFIG_XEN) += arch/arm/xen/
>>
>> That leaves a small difference in hypercall.o, which I think you can
>> handle with an #ifdef.
>>
>> I believe the reason why KVM does the more elaborate variant is that
>> they want to be able to build their code as a loadable module that
>> also includes code from virt/kvm, which you don''t need.
> 
> I thought we scrapped the idea of KVM as a loadable module on ARM, mainly
> due to the complexities with retrospective initialisation of HYP mode/EL2?
What if Hyp/EL2 support were dubbed regular kernel code and the rest of KVM
was made loadable?

Christopher

-- 
Employee of Qualcomm Innovation Center, Inc.
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
hosted by the Linux Foundation.

Catalin Marinas

2013-Jun-06 14:42 UTC

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Re: [PATCH v3 5/6] arm64/xen: introduce CONFIG_XEN and hypercall.S on ARM64

Hi Arnd,

On Wed, Jun 05, 2013 at 01:44:55PM +0100, Arnd Bergmann
wrote:> On Wednesday 05 June 2013 13:15:29 Stefano Stabellini wrote:
> > diff --git a/arch/arm64/Makefile b/arch/arm64/Makefile
> > index c95c5cb..79dd13d 100644
> > --- a/arch/arm64/Makefile
> > +++ b/arch/arm64/Makefile
> > @@ -37,6 +37,7 @@ TEXT_OFFSET := 0x00080000
> >  export TEXT_OFFSET GZFLAGS
> >  
> >  core-y         += arch/arm64/kernel/ arch/arm64/mm/
> > +core-$(CONFIG_XEN)             += arch/arm64/xen/
> >  libs-y         := arch/arm64/lib/ $(libs-y)
> >  libs-y         += $(LIBGCC)
> >  
> > diff --git a/arch/arm64/xen/Makefile b/arch/arm64/xen/Makefile
> > new file mode 100644
> > index 0000000..be24040
> > --- /dev/null
> > +++ b/arch/arm64/xen/Makefile
> > @@ -0,0 +1,2 @@
> > +xen-arm-y      += $(addprefix ../../arm/xen/, enlighten.o
grant-table.o)
> > +obj-y          := xen-arm.o hypercall.o
> 
> I think it would be nicer to redirect the entire directory, not just
> the enlighten.o and grant-table.o files. You could do in
arch/arm64/Makefile:
> 
> core-(CONFIG_XEN) += arch/arm/xen/
> 
> That leaves a small difference in hypercall.o, which I think you can
> handle with an #ifdef.
Sorry, I missed this part. I want to keep the AArch64 assembly under
arm64, even if it is small.

-- 
Catalin

Stefano Stabellini

2013-Jun-06 16:19 UTC

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Re: [PATCH v3 5/6] arm64/xen: introduce CONFIG_XEN and hypercall.S on ARM64

On Thu, 6 Jun 2013, Catalin Marinas wrote:> Hi Arnd,
> 
> On Wed, Jun 05, 2013 at 01:44:55PM +0100, Arnd Bergmann wrote:
> > On Wednesday 05 June 2013 13:15:29 Stefano Stabellini wrote:
> > > diff --git a/arch/arm64/Makefile b/arch/arm64/Makefile
> > > index c95c5cb..79dd13d 100644
> > > --- a/arch/arm64/Makefile
> > > +++ b/arch/arm64/Makefile
> > > @@ -37,6 +37,7 @@ TEXT_OFFSET := 0x00080000
> > >  export TEXT_OFFSET GZFLAGS
> > >  
> > >  core-y         += arch/arm64/kernel/ arch/arm64/mm/
> > > +core-$(CONFIG_XEN)             += arch/arm64/xen/
> > >  libs-y         := arch/arm64/lib/ $(libs-y)
> > >  libs-y         += $(LIBGCC)
> > >  
> > > diff --git a/arch/arm64/xen/Makefile b/arch/arm64/xen/Makefile
> > > new file mode 100644
> > > index 0000000..be24040
> > > --- /dev/null
> > > +++ b/arch/arm64/xen/Makefile
> > > @@ -0,0 +1,2 @@
> > > +xen-arm-y      += $(addprefix ../../arm/xen/, enlighten.o
grant-table.o)
> > > +obj-y          := xen-arm.o hypercall.o
> > 
> > I think it would be nicer to redirect the entire directory, not just
> > the enlighten.o and grant-table.o files. You could do in
arch/arm64/Makefile:
> > 
> > core-(CONFIG_XEN) += arch/arm/xen/
> > 
> > That leaves a small difference in hypercall.o, which I think you can
> > handle with an #ifdef.
> 
> Sorry, I missed this part. I want to keep the AArch64 assembly under
> arm64, even if it is small.
That''s fine, I don''t have a strong opinion on this, I am happy
either way.

In this case the v3 of the series is the one we want.
I''ll submit a pull request to you for it during the next couple of
days.

Xen devel - Jun 2013 - [PATCH v3 0/6] Introduce Xen support to ARM64

[PATCH v3 0/6] Introduce Xen support to ARM64

[PATCH v3 1/6] arm/xen: define xen_remap as ioremap_cached

[PATCH v3 2/6] arm64/xen: introduce asm/xen header files on arm64

[PATCH v3 3/6] arm64/xen: implement ioremap_cached on arm64

[PATCH v3 4/6] arm64/xen: use XEN_IO_PROTO_ABI_ARM on ARM64

[PATCH v3 5/6] arm64/xen: introduce CONFIG_XEN and hypercall.S on ARM64

[PATCH v3 6/6] MAINTAINERS: add myself as arm64/xen maintainer

Re: [PATCH v3 5/6] arm64/xen: introduce CONFIG_XEN and hypercall.S on ARM64

Re: [PATCH v3 6/6] MAINTAINERS: add myself as arm64/xen maintainer

Re: [PATCH v3 5/6] arm64/xen: introduce CONFIG_XEN and hypercall.S on ARM64

Re: [PATCH v3 5/6] arm64/xen: introduce CONFIG_XEN and hypercall.S on ARM64

Re: [PATCH v3 5/6] arm64/xen: introduce CONFIG_XEN and hypercall.S on ARM64

Re: [PATCH v3 5/6] arm64/xen: introduce CONFIG_XEN and hypercall.S on ARM64

Re: [PATCH v3 6/6] MAINTAINERS: add myself as arm64/xen maintainer

Re: [PATCH v3 5/6] arm64/xen: introduce CONFIG_XEN and hypercall.S on ARM64

Re: [PATCH v3 5/6] arm64/xen: introduce CONFIG_XEN and hypercall.S on ARM64

Re: [PATCH v3 5/6] arm64/xen: introduce CONFIG_XEN and hypercall.S on ARM64