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[Qemu-devel] [PATCH 2/4] linux-user: Introduce qemu_vmalloc_guest_safe
From: |
Jan Kiszka |
Subject: |
[Qemu-devel] [PATCH 2/4] linux-user: Introduce qemu_vmalloc_guest_safe |
Date: |
Tue, 15 Jul 2008 00:09:58 +0200 |
User-agent: |
Mozilla/5.0 (X11; U; Linux i686 (x86_64); de; rv:1.8.1.12) Gecko/20080226 SUSE/2.0.0.12-1.1 Thunderbird/2.0.0.12 Mnenhy/0.7.5.666 |
Add qemu_vmalloc_guest_safe to allocate memory from a region that are
reachable by user-space guests. Addresses returned by this function can
safely be provided to h2g.
Signed-off-by: Jan Kiszka <address@hidden>
---
linux-user/mmap.c | 37 +++++++++++++++++++++++++++++++++++++
linux-user/qemu.h | 1 +
2 files changed, 38 insertions(+)
Index: b/linux-user/mmap.c
===================================================================
--- a/linux-user/mmap.c
+++ b/linux-user/mmap.c
@@ -94,6 +94,43 @@ void *qemu_vmalloc(size_t size)
return p;
}
+void *qemu_vmalloc_guest_safe(size_t size)
+{
+#if TARGET_LONG_BIT < HOST_LONG_BITS
+ void *p;
+ unsigned long addr;
+ abi_ulong guest_start;
+
+ mmap_lock();
+
+ /* Ensure we allocate from the guest-reachable rage */
+ size = HOST_PAGE_ALIGN(size);
+ guest_start = mmap_find_vma(0, size);
+ if (guest_start == (abi_ulong)-1) {
+ p = NULL;
+ goto unlock_exit;
+ }
+
+ /* Use map and mark the pages as used. */
+ p = mmap(g2h(guest_start), size, PROT_READ | PROT_WRITE,
+ MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
+ if (p == MAP_FAILED) {
+ p = NULL;
+ goto unlock_exit;
+ }
+
+ addr = (unsigned long)p;
+ page_set_flags(addr & TARGET_PAGE_MASK, TARGET_PAGE_ALIGN(addr + size),
+ PAGE_RESERVED);
+
+unlock_exit:
+ mmap_unlock();
+ return p;
+#else
+ return qemu_vmalloc(size);
+#endif
+}
+
void *qemu_malloc(size_t size)
{
char * p;
Index: b/linux-user/qemu.h
===================================================================
--- a/linux-user/qemu.h
+++ b/linux-user/qemu.h
@@ -247,6 +247,7 @@ void mmap_unlock(void);
void mmap_fork_start(void);
void mmap_fork_end(int child);
#endif
+void *qemu_vmalloc_guest_safe(size_t size);
/* user access */