[Xen-changelog] [xen master] hvmloader/pci: try to avoid placing BARs in RMRRs

[patchbot@xxxxxxx]

commit b730fc3e157a7b401305cecad7fcefee28340e2c
Author:     George Dunlap <george.dunlap@xxxxxxxxxxxxx>
AuthorDate: Wed Jul 22 15:24:49 2015 +0100
Commit:     Ian Jackson <Ian.Jackson@xxxxxxxxxxxxx>
CommitDate: Thu Jul 23 13:45:25 2015 +0100

    hvmloader/pci: try to avoid placing BARs in RMRRs
    
    Try to avoid placing PCI BARs over RMRRs:
    
    - If mmio_hole_size is not specified, and the existing MMIO range has
      RMRRs in it, and there is space to expand the hole in lowmem without
      moving more memory, then make the MMIO hole as large as possible.
    
    - When placing RMRRs, find the next RMRR higher than the current base
      in the lowmem mmio hole.  If it overlaps, skip ahead of it and find
      the next one.
    
    This certainly won't work in all cases, but it should work in a
    significant number of cases.  Additionally, users should be able to
    work around problems by setting mmio_hole_size larger in the guest
    config.
    
    Signed-off-by: George Dunlap <george.dunlap@xxxxxxxxxxxxx>
    Signed-off-by: Tiejun Chen <tiejun.chen@xxxxxxxxx>
    Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx>
    Release-acked-by: Wei Liu <wei.liu2@xxxxxxxxxx>
---
 tools/firmware/hvmloader/pci.c |   64 ++++++++++++++++++++++++++++++++++++++++
 1 files changed, 64 insertions(+), 0 deletions(-)

diff --git a/tools/firmware/hvmloader/pci.c b/tools/firmware/hvmloader/pci.c
index 5ff87a7..ff81fba 100644
--- a/tools/firmware/hvmloader/pci.c
+++ b/tools/firmware/hvmloader/pci.c
@@ -38,6 +38,45 @@ uint64_t pci_hi_mem_start = 0, pci_hi_mem_end = 0;
 enum virtual_vga virtual_vga = VGA_none;
 unsigned long igd_opregion_pgbase = 0;
 
+/* Check if the specified range conflicts with any reserved device memory. */
+static bool check_overlap_all(uint64_t start, uint64_t size)
+{
+    unsigned int i;
+
+    for ( i = 0; i < memory_map.nr_map; i++ )
+    {
+        if ( memory_map.map[i].type == E820_RESERVED &&
+             check_overlap(start, size,
+                           memory_map.map[i].addr,
+                           memory_map.map[i].size) )
+            return true;
+    }
+
+    return false;
+}
+
+/* Find the lowest RMRR ending above base but below 4G. */
+static int find_next_rmrr(uint32_t base)
+{
+    unsigned int i;
+    int next_rmrr = -1;
+    uint64_t end, min_end = 1ULL << 32;
+
+    for ( i = 0; i < memory_map.nr_map ; i++ )
+    {
+        end = memory_map.map[i].addr + memory_map.map[i].size;
+
+        if ( memory_map.map[i].type == E820_RESERVED &&
+             end > base && end <= min_end )
+        {
+            next_rmrr = i;
+            min_end = end;
+        }
+    }
+
+    return next_rmrr;
+}
+
 void pci_setup(void)
 {
     uint8_t is_64bar, using_64bar, bar64_relocate = 0;
@@ -46,6 +85,7 @@ void pci_setup(void)
     uint32_t vga_devfn = 256;
     uint16_t class, vendor_id, device_id;
     unsigned int bar, pin, link, isa_irq;
+    int next_rmrr;
 
     /* Resources assignable to PCI devices via BARs. */
     struct resource {
@@ -299,6 +339,15 @@ void pci_setup(void)
                     || (((pci_mem_start << 1) >> PAGE_SHIFT)
                         >= hvm_info->low_mem_pgend)) )
             pci_mem_start <<= 1;
+
+        /*
+         * Try to accommodate RMRRs in our MMIO region on a best-effort basis.
+         * If we have RMRRs in the range, then make pci_mem_start just after
+         * hvm_info->low_mem_pgend.
+         */
+        if ( pci_mem_start > (hvm_info->low_mem_pgend << PAGE_SHIFT) &&
+             check_overlap_all(pci_mem_start, pci_mem_end-pci_mem_start) )
+            pci_mem_start = hvm_info->low_mem_pgend << PAGE_SHIFT;
     }
 
     if ( mmio_total > (pci_mem_end - pci_mem_start) )
@@ -352,6 +401,8 @@ void pci_setup(void)
     io_resource.base = 0xc000;
     io_resource.max = 0x10000;
 
+    next_rmrr = find_next_rmrr(pci_mem_start);
+
     /* Assign iomem and ioport resources in descending order of size. */
     for ( i = 0; i < nr_bars; i++ )
     {
@@ -407,6 +458,19 @@ void pci_setup(void)
         }
 
         base = (resource->base  + bar_sz - 1) & ~(uint64_t)(bar_sz - 1);
+
+        /* If we're using mem_resource, check for RMRR conflicts. */
+        while ( resource == &mem_resource &&
+                next_rmrr >= 0 &&
+                check_overlap(base, bar_sz,
+                              memory_map.map[next_rmrr].addr,
+                              memory_map.map[next_rmrr].size) )
+        {
+            base = memory_map.map[next_rmrr].addr + 
memory_map.map[next_rmrr].size;
+            base = (base + bar_sz - 1) & ~(bar_sz - 1);
+            next_rmrr = find_next_rmrr(base);
+        }
+
         bar_data |= (uint32_t)base;
         bar_data_upper = (uint32_t)(base >> 32);
         base += bar_sz;
--
generated by git-patchbot for /home/xen/git/xen.git#master

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