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[Qemu-devel] [PATCH 25/55] exec: add page_mask for flatview_do_translate
From: |
Michael Roth |
Subject: |
[Qemu-devel] [PATCH 25/55] exec: add page_mask for flatview_do_translate |
Date: |
Wed, 6 Dec 2017 13:16:18 -0600 |
From: Peter Xu <address@hidden>
The function is originally used for flatview_space_translate() and what
we care about most is (xlat, plen) range. However for iotlb requests, we
don't really care about "plen", but the size of the page that "xlat" is
located on. While, plen cannot really contain this information.
A simple example to show why "plen" is not good for IOTLB translations:
E.g., for huge pages, it is possible that guest mapped 1G huge page on
device side that used this GPA range:
0x100000000 - 0x13fffffff
Then let's say we want to translate one IOVA that finally mapped to GPA
0x13ffffe00 (which is located on this 1G huge page). Then here we'll
get:
(xlat, plen) = (0x13fffe00, 0x200)
So the IOTLB would be only covering a very small range since from
"plen" (which is 0x200 bytes) we cannot tell the size of the page.
Actually we can really know that this is a huge page - we just throw the
information away in flatview_do_translate().
This patch introduced "page_mask" optional parameter to capture that
page mask info. Also, I made "plen" an optional parameter as well, with
some comments for the whole function.
No functional change yet.
Signed-off-by: Peter Xu <address@hidden>
Signed-off-by: Maxime Coquelin <address@hidden>
Message-Id: <address@hidden>
Signed-off-by: Paolo Bonzini <address@hidden>
(cherry picked from commit d5e5fafd11be4458443c43f19c1ebdd24d99a751)
Signed-off-by: Michael Roth <address@hidden>
---
exec.c | 51 +++++++++++++++++++++++++++++++++++++++++++++------
1 file changed, 45 insertions(+), 6 deletions(-)
diff --git a/exec.c b/exec.c
index b1f29d35d8..2fd65dc3f2 100644
--- a/exec.c
+++ b/exec.c
@@ -468,11 +468,29 @@ address_space_translate_internal(AddressSpaceDispatch *d,
hwaddr addr, hwaddr *x
return section;
}
-/* Called from RCU critical section */
+/**
+ * flatview_do_translate - translate an address in FlatView
+ *
+ * @fv: the flat view that we want to translate on
+ * @addr: the address to be translated in above address space
+ * @xlat: the translated address offset within memory region. It
+ * cannot be @NULL.
+ * @plen_out: valid read/write length of the translated address. It
+ * can be @NULL when we don't care about it.
+ * @page_mask_out: page mask for the translated address. This
+ * should only be meaningful for IOMMU translated
+ * addresses, since there may be huge pages that this bit
+ * would tell. It can be @NULL if we don't care about it.
+ * @is_write: whether the translation operation is for write
+ * @is_mmio: whether this can be MMIO, set true if it can
+ *
+ * This function is called from RCU critical section
+ */
static MemoryRegionSection flatview_do_translate(FlatView *fv,
hwaddr addr,
hwaddr *xlat,
- hwaddr *plen,
+ hwaddr *plen_out,
+ hwaddr *page_mask_out,
bool is_write,
bool is_mmio,
AddressSpace **target_as)
@@ -481,11 +499,17 @@ static MemoryRegionSection flatview_do_translate(FlatView
*fv,
MemoryRegionSection *section;
IOMMUMemoryRegion *iommu_mr;
IOMMUMemoryRegionClass *imrc;
+ hwaddr page_mask = (hwaddr)(-1);
+ hwaddr plen = (hwaddr)(-1);
+
+ if (plen_out) {
+ plen = *plen_out;
+ }
for (;;) {
section = address_space_translate_internal(
flatview_to_dispatch(fv), addr, &addr,
- plen, is_mmio);
+ &plen, is_mmio);
iommu_mr = memory_region_get_iommu(section->mr);
if (!iommu_mr) {
@@ -497,7 +521,8 @@ static MemoryRegionSection flatview_do_translate(FlatView
*fv,
IOMMU_WO : IOMMU_RO);
addr = ((iotlb.translated_addr & ~iotlb.addr_mask)
| (addr & iotlb.addr_mask));
- *plen = MIN(*plen, (addr | iotlb.addr_mask) - addr + 1);
+ page_mask &= iotlb.addr_mask;
+ plen = MIN(plen, (addr | iotlb.addr_mask) - addr + 1);
if (!(iotlb.perm & (1 << is_write))) {
goto translate_fail;
}
@@ -508,6 +533,19 @@ static MemoryRegionSection flatview_do_translate(FlatView
*fv,
*xlat = addr;
+ if (page_mask == (hwaddr)(-1)) {
+ /* Not behind an IOMMU, use default page size. */
+ page_mask = ~TARGET_PAGE_MASK;
+ }
+
+ if (page_mask_out) {
+ *page_mask_out = page_mask;
+ }
+
+ if (plen_out) {
+ *plen_out = plen;
+ }
+
return *section;
translate_fail:
@@ -526,7 +564,7 @@ IOMMUTLBEntry address_space_get_iotlb_entry(AddressSpace
*as, hwaddr addr,
/* This can never be MMIO. */
section = flatview_do_translate(address_space_to_flatview(as), addr,
- &xlat, &plen, is_write, false, &as);
+ &xlat, &plen, NULL, is_write, false, &as);
/* Illegal translation */
if (section.mr == &io_mem_unassigned) {
@@ -570,7 +608,8 @@ MemoryRegion *flatview_translate(FlatView *fv, hwaddr addr,
hwaddr *xlat,
AddressSpace *as = NULL;
/* This can be MMIO, so setup MMIO bit. */
- section = flatview_do_translate(fv, addr, xlat, plen, is_write, true, &as);
+ section = flatview_do_translate(fv, addr, xlat, plen, NULL,
+ is_write, true, &as);
mr = section.mr;
if (xen_enabled() && memory_access_is_direct(mr, is_write)) {
--
2.11.0
- [Qemu-devel] [PATCH 20/55] memory: Get rid of address_space_init_shareable, (continued)
- [Qemu-devel] [PATCH 20/55] memory: Get rid of address_space_init_shareable, Michael Roth, 2017/12/06
- [Qemu-devel] [PATCH 19/55] memory: Do not allocate FlatView in address_space_init, Michael Roth, 2017/12/06
- [Qemu-devel] [PATCH 17/55] memory: Move address_space_update_ioeventfds, Michael Roth, 2017/12/06
- [Qemu-devel] [PATCH 01/55] hw/ppc: CAS reset on early device hotplug, Michael Roth, 2017/12/06
- [Qemu-devel] [PATCH 22/55] memory: trace FlatView creation and destruction, Michael Roth, 2017/12/06
- [Qemu-devel] [PATCH 21/55] memory: Create FlatView directly, Michael Roth, 2017/12/06
- [Qemu-devel] [PATCH 23/55] memory: seek FlatView sharing candidates among children subregions, Michael Roth, 2017/12/06
- [Qemu-devel] [PATCH 24/55] memory: Share special empty FlatView, Michael Roth, 2017/12/06
- [Qemu-devel] [PATCH 27/55] memory: fix off-by-one error in memory_region_notify_one(), Michael Roth, 2017/12/06
- [Qemu-devel] [PATCH 29/55] qcow2: Fix unaligned preallocated truncation, Michael Roth, 2017/12/06
- [Qemu-devel] [PATCH 25/55] exec: add page_mask for flatview_do_translate,
Michael Roth <=
- [Qemu-devel] [PATCH 26/55] exec: simplify address_space_get_iotlb_entry, Michael Roth, 2017/12/06
- [Qemu-devel] [PATCH 02/55] hw/usb/bus: Remove bad object_unparent() from usb_try_create_simple(), Michael Roth, 2017/12/06
- [Qemu-devel] [PATCH 32/55] nios2: define tcg_env, Michael Roth, 2017/12/06
- [Qemu-devel] [PATCH 33/55] io: monitor encoutput buffer size from websocket GSource, Michael Roth, 2017/12/06
- [Qemu-devel] [PATCH 34/55] ppc: fix setting of compat mode, Michael Roth, 2017/12/06
- [Qemu-devel] [PATCH 28/55] hw/sd: fix out-of-bounds check for multi block reads, Michael Roth, 2017/12/06
- [Qemu-devel] [PATCH 30/55] qcow2: Always execute preallocate() in a coroutine, Michael Roth, 2017/12/06
- [Qemu-devel] [PATCH 31/55] iotests: Add cluster_size=64k to 125, Michael Roth, 2017/12/06
- [Qemu-devel] [PATCH 36/55] hw/intc/arm_gicv3_its: Don't abort on table save failure, Michael Roth, 2017/12/06
- [Qemu-devel] [PATCH 40/55] util/stats64: Fix min/max comparisons, Michael Roth, 2017/12/06