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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [PATCH v2] x86/msi: dynamically map pages for MSI-X tables
Xen reserves a constant number of pages that can be used for mapping
MSI-X tables. This limit is defined by FIX_MSIX_MAX_PAGES in fixmap.h.
Reserving a fixed number of pages could result in an -ENOMEM if a
device requests a new page when the fixmap limit is exhausted and will
necessitate manually adjusting the limit before compilation.
To avoid the issues with the current fixmap implementation, we modify
the MSI-X page mapping logic to instead dynamically map new pages when
they are needed by making use of ioremap().
Note that this approach is not suitable for 32-bit architectures, where
the virtual address space is considerably smaller.
Signed-off-by: Ruben Hakobyan <hakor@xxxxxxxxxx>
---
Changelog:
* v2:
- Updated the commit message to talk about the potential use on 32-bit
architectures
- Addressed the various comments for improving the code
---
xen/arch/x86/include/asm/fixmap.h | 2 -
xen/arch/x86/include/asm/msi.h | 5 +--
xen/arch/x86/msi.c | 69 ++++++++-----------------------
3 files changed, 18 insertions(+), 58 deletions(-)
diff --git a/xen/arch/x86/include/asm/fixmap.h
b/xen/arch/x86/include/asm/fixmap.h
index 516ec3fa6c..139c3e2dcc 100644
--- a/xen/arch/x86/include/asm/fixmap.h
+++ b/xen/arch/x86/include/asm/fixmap.h
@@ -61,8 +61,6 @@ enum fixed_addresses {
FIX_ACPI_END = FIX_ACPI_BEGIN + NUM_FIXMAP_ACPI_PAGES - 1,
FIX_HPET_BASE,
FIX_TBOOT_SHARED_BASE,
- FIX_MSIX_IO_RESERV_BASE,
- FIX_MSIX_IO_RESERV_END = FIX_MSIX_IO_RESERV_BASE + FIX_MSIX_MAX_PAGES -1,
FIX_TBOOT_MAP_ADDRESS,
FIX_APEI_RANGE_BASE,
FIX_APEI_RANGE_END = FIX_APEI_RANGE_BASE + FIX_APEI_RANGE_MAX -1,
diff --git a/xen/arch/x86/include/asm/msi.h b/xen/arch/x86/include/asm/msi.h
index a53ade95c9..16c80c9883 100644
--- a/xen/arch/x86/include/asm/msi.h
+++ b/xen/arch/x86/include/asm/msi.h
@@ -55,9 +55,6 @@
#define MSI_ADDR_DEST_ID_MASK 0x00ff000
#define MSI_ADDR_DEST_ID(dest) (((dest) <<
MSI_ADDR_DEST_ID_SHIFT) & MSI_ADDR_DEST_ID_MASK)
-/* MAX fixed pages reserved for mapping MSIX tables. */
-#define FIX_MSIX_MAX_PAGES 512
-
struct msi_info {
pci_sbdf_t sbdf;
int irq;
@@ -213,7 +210,7 @@ struct arch_msix {
unsigned long first, last;
} table, pba;
int table_refcnt[MAX_MSIX_TABLE_PAGES];
- int table_idx[MAX_MSIX_TABLE_PAGES];
+ void __iomem *table_va[MAX_MSIX_TABLE_PAGES];
spinlock_t table_lock;
bool host_maskall, guest_maskall;
domid_t warned;
diff --git a/xen/arch/x86/msi.c b/xen/arch/x86/msi.c
index d0bf63df1d..57a84b394a 100644
--- a/xen/arch/x86/msi.c
+++ b/xen/arch/x86/msi.c
@@ -24,7 +24,6 @@
#include <asm/smp.h>
#include <asm/desc.h>
#include <asm/msi.h>
-#include <asm/fixmap.h>
#include <asm/p2m.h>
#include <mach_apic.h>
#include <io_ports.h>
@@ -39,75 +38,45 @@ boolean_param("msi", use_msi);
static void __pci_disable_msix(struct msi_desc *);
-/* bitmap indicate which fixed map is free */
-static DEFINE_SPINLOCK(msix_fixmap_lock);
-static DECLARE_BITMAP(msix_fixmap_pages, FIX_MSIX_MAX_PAGES);
-
-static int msix_fixmap_alloc(void)
-{
- int i, rc = -ENOMEM;
-
- spin_lock(&msix_fixmap_lock);
- for ( i = 0; i < FIX_MSIX_MAX_PAGES; i++ )
- if ( !test_bit(i, &msix_fixmap_pages) )
- break;
- if ( i == FIX_MSIX_MAX_PAGES )
- goto out;
- rc = FIX_MSIX_IO_RESERV_BASE + i;
- set_bit(i, &msix_fixmap_pages);
-
- out:
- spin_unlock(&msix_fixmap_lock);
- return rc;
-}
-
-static void msix_fixmap_free(int idx)
-{
- spin_lock(&msix_fixmap_lock);
- if ( idx >= FIX_MSIX_IO_RESERV_BASE )
- clear_bit(idx - FIX_MSIX_IO_RESERV_BASE, &msix_fixmap_pages);
- spin_unlock(&msix_fixmap_lock);
-}
-
-static int msix_get_fixmap(struct arch_msix *msix, u64 table_paddr,
+static void __iomem *msix_get_entry(struct arch_msix *msix, u64 table_paddr,
u64 entry_paddr)
{
long nr_page;
- int idx;
+ void __iomem *va = NULL;
nr_page = (entry_paddr >> PAGE_SHIFT) - (table_paddr >> PAGE_SHIFT);
if ( nr_page < 0 || nr_page >= MAX_MSIX_TABLE_PAGES )
- return -EINVAL;
+ return NULL;
spin_lock(&msix->table_lock);
if ( msix->table_refcnt[nr_page]++ == 0 )
{
- idx = msix_fixmap_alloc();
- if ( idx < 0 )
+ va = ioremap(round_pgdown(entry_paddr), PAGE_SIZE);
+ if ( va == NULL )
{
msix->table_refcnt[nr_page]--;
goto out;
}
- set_fixmap_nocache(idx, entry_paddr);
- msix->table_idx[nr_page] = idx;
+ msix->table_va[nr_page] = va;
}
else
- idx = msix->table_idx[nr_page];
+ va = msix->table_va[nr_page];
out:
spin_unlock(&msix->table_lock);
- return idx;
+ return va + (entry_paddr & ~PAGE_MASK);
}
-static void msix_put_fixmap(struct arch_msix *msix, int idx)
+static void msix_put_entry(struct arch_msix *msix, const void __iomem
*entry_va)
{
int i;
+ void __iomem *va = (void*)round_pgdown((unsigned long)entry_va);
spin_lock(&msix->table_lock);
for ( i = 0; i < MAX_MSIX_TABLE_PAGES; i++ )
{
- if ( msix->table_idx[i] == idx )
+ if ( msix->table_va[i] == va )
break;
}
if ( i == MAX_MSIX_TABLE_PAGES )
@@ -115,9 +84,8 @@ static void msix_put_fixmap(struct arch_msix *msix, int idx)
if ( --msix->table_refcnt[i] == 0 )
{
- clear_fixmap(idx);
- msix_fixmap_free(idx);
- msix->table_idx[i] = 0;
+ iounmap(va);
+ msix->table_va[i] = NULL;
}
out:
@@ -568,8 +536,7 @@ int msi_free_irq(struct msi_desc *entry)
}
if ( entry->msi_attrib.type == PCI_CAP_ID_MSIX )
- msix_put_fixmap(entry->dev->msix,
- virt_to_fix((unsigned long)entry->mask_base));
+ msix_put_entry(entry->dev->msix, entry->mask_base);
list_del(&entry->list);
xfree(entry);
@@ -892,10 +859,9 @@ static int msix_capability_init(struct pci_dev *dev,
{
/* Map MSI-X table region */
u64 entry_paddr = table_paddr + msi->entry_nr * PCI_MSIX_ENTRY_SIZE;
- int idx = msix_get_fixmap(msix, table_paddr, entry_paddr);
- void __iomem *base;
+ void __iomem *base = msix_get_entry(msix, table_paddr, entry_paddr);
- if ( idx < 0 )
+ if ( base == NULL )
{
if ( zap_on_error )
{
@@ -907,9 +873,8 @@ static int msix_capability_init(struct pci_dev *dev,
pci_conf_write16(dev->sbdf, msix_control_reg(pos), control);
xfree(entry);
- return idx;
+ return -ENOMEM;
}
- base = fix_to_virt(idx) + (entry_paddr & (PAGE_SIZE - 1));
/* Mask interrupt here */
writel(1, base + PCI_MSIX_ENTRY_VECTOR_CTRL_OFFSET);
--
2.40.1
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