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From: Julien Grall <julien@xen.org>
To: xen-devel@lists.xenproject.org
Cc: julien@xen.org, "Hongyan Xia" <hongyxia@amazon.com>,
	"Jan Beulich" <jbeulich@suse.com>,
	"Andrew Cooper" <andrew.cooper3@citrix.com>,
	"Roger Pau Monné" <roger.pau@citrix.com>, "Wei Liu" <wl@xen.org>,
	"Julien Grall" <jgrall@amazon.com>
Subject: [PATCH 14/22] x86/domain_page: remove the fast paths when mfn is not in the directmap
Date: Fri, 16 Dec 2022 11:48:45 +0000	[thread overview]
Message-ID: <20221216114853.8227-15-julien@xen.org> (raw)
In-Reply-To: <20221216114853.8227-1-julien@xen.org>

From: Hongyan Xia <hongyxia@amazon.com>

When mfn is not in direct map, never use mfn_to_virt for any mappings.

We replace mfn_x(mfn) <= PFN_DOWN(__pa(HYPERVISOR_VIRT_END - 1)) with
arch_mfns_in_direct_map(mfn, 1) because these two are equivalent. The
extra comparison in arch_mfns_in_direct_map() looks different but because
DIRECTMAP_VIRT_END is always higher, it does not make any difference.

Lastly, domain_page_map_to_mfn() needs to gain to a special case for
the PMAP.

Signed-off-by: Hongyan Xia <hongyxia@amazon.com>
Signed-off-by: Julien Grall <jgrall@amazon.com>

----
    Changes since Hongyan's version:
        * arch_mfn_in_direct_map() was renamed to arch_mfns_in_directmap()
        * add a special case for the PMAP in domain_page_map_to_mfn()
---
 xen/arch/x86/domain_page.c | 50 +++++++++++++++++++++++++++++++-------
 1 file changed, 41 insertions(+), 9 deletions(-)

diff --git a/xen/arch/x86/domain_page.c b/xen/arch/x86/domain_page.c
index 55e337aaf703..89caefc8a210 100644
--- a/xen/arch/x86/domain_page.c
+++ b/xen/arch/x86/domain_page.c
@@ -14,8 +14,10 @@
 #include <xen/sched.h>
 #include <xen/vmap.h>
 #include <asm/current.h>
+#include <asm/fixmap.h>
 #include <asm/flushtlb.h>
 #include <asm/hardirq.h>
+#include <asm/pmap.h>
 #include <asm/setup.h>
 
 static DEFINE_PER_CPU(struct vcpu *, override);
@@ -35,10 +37,11 @@ static inline struct vcpu *mapcache_current_vcpu(void)
     /*
      * When using efi runtime page tables, we have the equivalent of the idle
      * domain's page tables but current may point at another domain's VCPU.
-     * Return NULL as though current is not properly set up yet.
+     * Return the idle domains's vcpu on that core because the efi per-domain
+     * region (where the mapcache is) is in-sync with the idle domain.
      */
     if ( efi_rs_using_pgtables() )
-        return NULL;
+        return idle_vcpu[smp_processor_id()];
 
     /*
      * If guest_table is NULL, and we are running a paravirtualised guest,
@@ -77,18 +80,24 @@ void *map_domain_page(mfn_t mfn)
     struct vcpu_maphash_entry *hashent;
 
 #ifdef NDEBUG
-    if ( mfn_x(mfn) <= PFN_DOWN(__pa(HYPERVISOR_VIRT_END - 1)) )
+    if ( arch_mfns_in_directmap(mfn_x(mfn), 1) )
         return mfn_to_virt(mfn_x(mfn));
 #endif
 
     v = mapcache_current_vcpu();
-    if ( !v )
-        return mfn_to_virt(mfn_x(mfn));
+    if ( !v || !v->domain->arch.mapcache.inuse )
+    {
+        if ( arch_mfns_in_directmap(mfn_x(mfn), 1) )
+            return mfn_to_virt(mfn_x(mfn));
+        else
+        {
+            BUG_ON(system_state >= SYS_STATE_smp_boot);
+            return pmap_map(mfn);
+        }
+    }
 
     dcache = &v->domain->arch.mapcache;
     vcache = &v->arch.mapcache;
-    if ( !dcache->inuse )
-        return mfn_to_virt(mfn_x(mfn));
 
     perfc_incr(map_domain_page_count);
 
@@ -184,6 +193,12 @@ void unmap_domain_page(const void *ptr)
     if ( !va || va >= DIRECTMAP_VIRT_START )
         return;
 
+    if ( va >= FIXADDR_START && va < FIXADDR_TOP )
+    {
+        pmap_unmap((void *)ptr);
+        return;
+    }
+
     ASSERT(va >= MAPCACHE_VIRT_START && va < MAPCACHE_VIRT_END);
 
     v = mapcache_current_vcpu();
@@ -237,7 +252,7 @@ int mapcache_domain_init(struct domain *d)
     unsigned int bitmap_pages;
 
 #ifdef NDEBUG
-    if ( !mem_hotplug && max_page <= PFN_DOWN(__pa(HYPERVISOR_VIRT_END - 1)) )
+    if ( !mem_hotplug && arch_mfn_in_directmap(0, max_page) )
         return 0;
 #endif
 
@@ -308,7 +323,7 @@ void *map_domain_page_global(mfn_t mfn)
             local_irq_is_enabled()));
 
 #ifdef NDEBUG
-    if ( mfn_x(mfn) <= PFN_DOWN(__pa(HYPERVISOR_VIRT_END - 1)) )
+    if ( arch_mfn_in_directmap(mfn_x(mfn, 1)) )
         return mfn_to_virt(mfn_x(mfn));
 #endif
 
@@ -335,6 +350,23 @@ mfn_t domain_page_map_to_mfn(const void *ptr)
     if ( va >= DIRECTMAP_VIRT_START )
         return _mfn(virt_to_mfn(ptr));
 
+    /*
+     * The fixmap is stealing the top-end of the VMAP. So the check for
+     * the PMAP *must* happen first.
+     *
+     * Also, the fixmap translate a slot to an address backwards. The
+     * logic will rely on it to avoid any complexity. So check at
+     * compile time this will always hold.
+    */
+    BUILD_BUG_ON(fix_to_virt(FIX_PMAP_BEGIN) < fix_to_virt(FIX_PMAP_END));
+
+    if ( ((unsigned long)fix_to_virt(FIX_PMAP_END) <= va) &&
+         ((va & PAGE_MASK) <= (unsigned long)fix_to_virt(FIX_PMAP_BEGIN)) )
+    {
+        BUG_ON(system_state >= SYS_STATE_smp_boot);
+        return l1e_get_mfn(l1_fixmap[l1_table_offset(va)]);
+    }
+
     if ( va >= VMAP_VIRT_START && va < VMAP_VIRT_END )
         return vmap_to_mfn(va);
 
-- 
2.38.1



  parent reply	other threads:[~2022-12-16 12:17 UTC|newest]

Thread overview: 101+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-12-16 11:48 [PATCH 00/22] Remove the directmap Julien Grall
2022-12-16 11:48 ` [PATCH 01/22] xen/common: page_alloc: Re-order includes Julien Grall
2022-12-16 12:03   ` Jan Beulich
2022-12-23  9:29     ` Julien Grall
2023-01-23 21:29   ` Stefano Stabellini
2023-01-23 21:57     ` Julien Grall
2022-12-16 11:48 ` [PATCH 02/22] x86/setup: move vm_init() before acpi calls Julien Grall
2022-12-20 15:08   ` Jan Beulich
2022-12-21 10:18     ` Julien Grall
2022-12-21 10:22       ` Jan Beulich
2022-12-23  9:51         ` Julien Grall
2022-12-23  9:51     ` Julien Grall
2023-01-23 21:34   ` Stefano Stabellini
2022-12-16 11:48 ` [PATCH 03/22] acpi: vmap pages in acpi_os_alloc_memory Julien Grall
2022-12-16 12:07   ` Julien Grall
2022-12-20 15:15   ` Jan Beulich
2022-12-21 10:23     ` Julien Grall
2023-01-23 21:39   ` Stefano Stabellini
2022-12-16 11:48 ` [PATCH 04/22] xen/numa: vmap the pages for memnodemap Julien Grall
2022-12-20 15:25   ` Jan Beulich
2022-12-16 11:48 ` [PATCH 05/22] x86/srat: vmap the pages for acpi_slit Julien Grall
2022-12-20 15:30   ` Jan Beulich
2022-12-23 11:31     ` Julien Grall
2023-01-04 10:23       ` Jan Beulich
2023-01-12 23:15         ` Julien Grall
2023-01-13  9:16           ` Jan Beulich
2023-01-13  9:17             ` Julien Grall
2023-01-30 19:27       ` Julien Grall
2023-01-31  9:11         ` Jan Beulich
2023-01-31 21:37           ` Julien Grall
2022-12-16 11:48 ` [PATCH 06/22] x86: map/unmap pages in restore_all_guests Julien Grall
2022-12-22 11:12   ` Jan Beulich
2022-12-23 12:22     ` Julien Grall
2023-01-04 10:27       ` Jan Beulich
2023-01-12 23:20         ` Julien Grall
2023-01-13  9:22           ` Jan Beulich
2023-06-22 10:44             ` Julien Grall
2023-06-22 13:19               ` Jan Beulich
2022-12-16 11:48 ` [PATCH 07/22] x86/pv: domheap pages should be mapped while relocating initrd Julien Grall
2022-12-22 11:18   ` Jan Beulich
2022-12-16 11:48 ` [PATCH 08/22] x86/pv: rewrite how building PV dom0 handles domheap mappings Julien Grall
2022-12-22 11:48   ` Jan Beulich
2024-01-10 12:50     ` El Yandouzi, Elias
2022-12-16 11:48 ` [PATCH 09/22] x86: lift mapcache variable to the arch level Julien Grall
2022-12-22 12:53   ` Jan Beulich
2022-12-16 11:48 ` [PATCH 10/22] x86/mapcache: initialise the mapcache for the idle domain Julien Grall
2022-12-22 13:06   ` Jan Beulich
2024-01-10 16:24     ` Elias El Yandouzi
2024-01-11  7:53       ` Jan Beulich
2022-12-16 11:48 ` [PATCH 11/22] x86: add a boot option to enable and disable the direct map Julien Grall
2022-12-22 13:24   ` Jan Beulich
2024-01-11 10:47     ` Elias El Yandouzi
2024-01-11 11:53       ` Jan Beulich
2024-01-11 12:25         ` Julien Grall
2024-01-11 14:09           ` Jan Beulich
2024-01-11 18:25             ` Elias El Yandouzi
2024-01-12  7:47               ` Jan Beulich
2024-01-15 14:50                 ` Elias El Yandouzi
2024-01-16  8:30                   ` Jan Beulich
2023-01-23 21:45   ` Stefano Stabellini
2023-01-23 22:01     ` Julien Grall
2022-12-16 11:48 ` [PATCH 12/22] xen/arm: fixmap: Rename the fixmap slots to follow the x86 convention Julien Grall
2022-12-22 13:29   ` Jan Beulich
2023-01-06 14:54   ` Henry Wang
2023-01-23 21:47   ` Stefano Stabellini
2022-12-16 11:48 ` [PATCH 13/22] xen/x86: Add support for the PMAP Julien Grall
2023-01-05 16:46   ` Jan Beulich
2023-01-05 17:50     ` Julien Grall
2023-01-06  7:17       ` Jan Beulich
2022-12-16 11:48 ` Julien Grall [this message]
2023-01-11 14:11   ` [PATCH 14/22] x86/domain_page: remove the fast paths when mfn is not in the directmap Jan Beulich
2024-01-11 14:22     ` Elias El Yandouzi
2022-12-16 11:48 ` [PATCH 15/22] xen/page_alloc: add a path for xenheap when there is no direct map Julien Grall
2023-01-11 14:23   ` Jan Beulich
2022-12-16 11:48 ` [PATCH 16/22] x86/setup: leave early boot slightly earlier Julien Grall
2023-01-11 14:34   ` Jan Beulich
2022-12-16 11:48 ` [PATCH 17/22] x86/setup: vmap heap nodes when they are outside the direct map Julien Grall
2023-01-11 14:39   ` Jan Beulich
2023-01-23 22:03   ` Stefano Stabellini
2023-01-23 22:23     ` Julien Grall
2023-01-23 22:56       ` Stefano Stabellini
2022-12-16 11:48 ` [PATCH 18/22] x86/setup: do not create valid mappings when directmap=no Julien Grall
2023-01-11 14:47   ` Jan Beulich
2022-12-16 11:48 ` [PATCH 19/22] xen/arm32: mm: Rename 'first' to 'root' in init_secondary_pagetables() Julien Grall
2023-01-06 14:54   ` Henry Wang
2023-01-23 22:06   ` Stefano Stabellini
2022-12-16 11:48 ` [PATCH 20/22] xen/arm64: mm: Use per-pCPU page-tables Julien Grall
2023-01-06 14:54   ` Henry Wang
2023-01-06 15:44     ` Julien Grall
2023-01-07  2:22       ` Henry Wang
2023-01-23 22:21   ` Stefano Stabellini
2022-12-16 11:48 ` [PATCH 21/22] xen/arm64: Implement a mapcache for arm64 Julien Grall
2023-01-06 14:55   ` Henry Wang
2023-01-23 22:34   ` Stefano Stabellini
2022-12-16 11:48 ` [PATCH 22/22] xen/arm64: Allow the admin to enable/disable the directmap Julien Grall
2023-01-06 14:55   ` Henry Wang
2023-01-23 22:52   ` Stefano Stabellini
2023-01-23 23:09     ` Julien Grall
2023-01-24  0:12       ` Stefano Stabellini
2023-01-24 18:06         ` Julien Grall
2023-01-24 20:48           ` Stefano Stabellini

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