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Re: [Xen-devel] [PATCH v8 5/6] iommu: tidy up iommu_use_hap_pt() and need_iommu_pt_sync() macros

Hi Paul, On 9/6/19 8:59 AM, Paul Durrant wrote:

-----Original Message-----
From: Julien Grall <julien.grall@xxxxxxx>
Sent: 05 September 2019 20:38
To: Paul Durrant <Paul.Durrant@xxxxxxxxxx>; xen-devel@xxxxxxxxxxxxxxxxxxxx
Cc: Jan Beulich <jbeulich@xxxxxxxx>; Andrew Cooper <Andrew.Cooper3@xxxxxxxxxx>; 
George Dunlap
<George.Dunlap@xxxxxxxxxx>; Ian Jackson <Ian.Jackson@xxxxxxxxxx>; Konrad 
Rzeszutek Wilk
<konrad.wilk@xxxxxxxxxx>; Stefano Stabellini <sstabellini@xxxxxxxxxx>; Tim (Xen.org) 
<tim@xxxxxxx>;
Wei Liu <wl@xxxxxxx>; Volodymyr Babchuk <Volodymyr_Babchuk@xxxxxxxx>; Roger Pau 
Monne
<roger.pau@xxxxxxxxxx>
Subject: Re: [PATCH v8 5/6] iommu: tidy up iommu_use_hap_pt() and 
need_iommu_pt_sync() macros

Hi Paul,

On 9/2/19 3:50 PM, Paul Durrant wrote:

Thes macros really ought to live in the common xen/iommu.h header rather
then being distributed amongst architecture specific iommu headers and
xen/sched.h. This patch moves them there.

NOTE: Disabling 'sharept' in the command line iommu options should really
        be hard error on ARM (as opposed to just being ignored), so define
        'iommu_hap_pt_share' to be true for ARM then then gate parsing the
        command line option on '#ifndef iommu_hap_pt_share'.

Signed-off-by: Paul Durrant <paul.durrant@xxxxxxxxxx>
Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx>
---
Cc: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
Cc: George Dunlap <George.Dunlap@xxxxxxxxxxxxx>
Cc: Ian Jackson <ian.jackson@xxxxxxxxxxxxx>
Cc: Julien Grall <julien.grall@xxxxxxx>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
Cc: Stefano Stabellini <sstabellini@xxxxxxxxxx>
Cc: Tim Deegan <tim@xxxxxxx>
Cc: Wei Liu <wl@xxxxxxx>
Cc: Volodymyr Babchuk <Volodymyr_Babchuk@xxxxxxxx>
Cc: "Roger Pau Monné" <roger.pau@xxxxxxxxxx>

Previously part of 
https://lists.xenproject.org/archives/html/xen-devel/2019-07/msg02267.html

v7:
   - Re-work the ARM handling of 'sharept' as suggested by Jan
   - Make sure that need_iommu_pt_sync() always evaluates its argument
---
   xen/drivers/passthrough/iommu.c |  8 +++++++-
   xen/include/asm-arm/iommu.h     |  3 ---
   xen/include/asm-x86/iommu.h     |  4 ----
   xen/include/xen/iommu.h         | 19 ++++++++++++++++++-
   xen/include/xen/sched.h         |  6 ------
   5 files changed, 25 insertions(+), 15 deletions(-)

diff --git a/xen/drivers/passthrough/iommu.c b/xen/drivers/passthrough/iommu.c
index 4f71db95ea..aaf3b9fac0 100644
--- a/xen/drivers/passthrough/iommu.c
+++ b/xen/drivers/passthrough/iommu.c
@@ -49,7 +49,11 @@ int8_t __hwdom_initdata iommu_hwdom_reserved = -1;
    * default until we find a good solution to resolve it.
    */
   bool_t __read_mostly iommu_intpost;
-bool_t __read_mostly iommu_hap_pt_share = 1;
+
+#ifndef iommu_hap_pt_share
+bool __read_mostly iommu_hap_pt_share = true;
+#endif
+
   bool_t __read_mostly iommu_debug;
   bool_t __read_mostly amd_iommu_perdev_intremap = 1;

@@ -102,8 +106,10 @@ static int __init parse_iommu_param(const char *s)
               iommu_hwdom_passthrough = val;
           else if ( (val = parse_boolean("dom0-strict", s, ss)) >= 0 )
               iommu_hwdom_strict = val;
+#ifndef iommu_hap_pt_share
           else if ( (val = parse_boolean("sharept", s, ss)) >= 0 )
               iommu_hap_pt_share = val;
+#endif
           else
               rc = -EINVAL;

diff --git a/xen/include/asm-arm/iommu.h b/xen/include/asm-arm/iommu.h
index 1577e83d2b..77a94b29eb 100644
--- a/xen/include/asm-arm/iommu.h
+++ b/xen/include/asm-arm/iommu.h
@@ -20,9 +20,6 @@ struct arch_iommu
       void *priv;
   };

-/* Always share P2M Table between the CPU and the IOMMU */
-#define iommu_use_hap_pt(d) is_iommu_enabled(d)
-
   const struct iommu_ops *iommu_get_ops(void);
   void iommu_set_ops(const struct iommu_ops *ops);

diff --git a/xen/include/asm-x86/iommu.h b/xen/include/asm-x86/iommu.h
index 5071afd6a5..85741f7c96 100644
--- a/xen/include/asm-x86/iommu.h
+++ b/xen/include/asm-x86/iommu.h
@@ -86,10 +86,6 @@ struct iommu_init_ops {

   extern const struct iommu_init_ops *iommu_init_ops;

-/* Are we using the domain P2M table as its IOMMU pagetable? */
-#define iommu_use_hap_pt(d) \
-    (hap_enabled(d) && is_iommu_enabled(d) && iommu_hap_pt_share)
-
   void iommu_update_ire_from_apic(unsigned int apic, unsigned int reg, 
unsigned int value);
   unsigned int iommu_read_apic_from_ire(unsigned int apic, unsigned int reg);
   int iommu_setup_hpet_msi(struct msi_desc *);
diff --git a/xen/include/xen/iommu.h b/xen/include/xen/iommu.h
index 4b6871936c..87f9129b99 100644
--- a/xen/include/xen/iommu.h
+++ b/xen/include/xen/iommu.h
@@ -55,7 +55,13 @@ static inline bool_t dfn_eq(dfn_t x, dfn_t y)
   extern bool_t iommu_enable, iommu_enabled;
   extern bool_t force_iommu, iommu_verbose, iommu_igfx;
   extern bool_t iommu_snoop, iommu_qinval, iommu_intremap, iommu_intpost;
-extern bool_t iommu_hap_pt_share;
+
+#ifdef CONFIG_ARM
+#define iommu_hap_pt_share true
+#else
+extern bool iommu_hap_pt_share;
+#endif


I don't particularly like #ifdef CONFIG_<ARCH> in common header. How
about other arch? I can see two solutions:

1) Move the define in asm/iommu.h. This would require to move the
declaration a bit later and then protect as you did in iommu.c
2) Replace CONFIG_ARM with a new Kconfig selected by Arm only so far.


I had wondered about a Kconfig but I can't really think of a good name. How 
about CONFIG_FORCE_PT_SHARE?

I would add "IOMMU" in the name just to make clear this is related to

IOMMU. So maybe CONFIG_IOMMU_FORCE_PT_SHARE.

Cheers, -- Julien Grall _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxxxxxxxxx https://lists.xenproject.org/mailman/listinfo/xen-devel

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