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authorPeter Maydell <peter.maydell@linaro.org>2016-10-24 16:26:49 +0100
committerPeter Maydell <peter.maydell@linaro.org>2016-10-24 16:26:49 +0100
commit20bccb82ff3ea09bcb7c4ee226d3160cab15f7da (patch)
treebeb472fa034fe9e742c571f678982235695f29eb /include/qemu-common.h
parent66ec9f49399f0a9fa13ee77c472caba0de2773fc (diff)
downloadqemu-arm-20bccb82ff3ea09bcb7c4ee226d3160cab15f7da.tar.gz
cpu: Support a target CPU having a variable page size
Support target CPUs having a page size which isn't knownn at compile time. To use this, the CPU implementation should: * define TARGET_PAGE_BITS_VARY * not define TARGET_PAGE_BITS * define TARGET_PAGE_BITS_MIN to the smallest value it might possibly want for TARGET_PAGE_BITS * call set_preferred_target_page_bits() in its realize function to indicate the actual preferred target page size for the CPU (and report any error from it) In CONFIG_USER_ONLY, the CPU implementation should continue to define TARGET_PAGE_BITS appropriately for the guest OS page size. Machines which want to take advantage of having the page size something larger than TARGET_PAGE_BITS_MIN must set the MachineClass minimum_page_bits field to a value which they guarantee will be no greater than the preferred page size for any CPU they create. Note that changing the target page size by setting minimum_page_bits is a migration compatibility break for that machine. For debugging purposes, attempts to use TARGET_PAGE_SIZE before it has been finally confirmed will assert. Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Richard Henderson <rth@twiddle.net>
Diffstat (limited to 'include/qemu-common.h')
-rw-r--r--include/qemu-common.h12
1 files changed, 12 insertions, 0 deletions
diff --git a/include/qemu-common.h b/include/qemu-common.h
index 9e8b0bd991..7e6e4feb4b 100644
--- a/include/qemu-common.h
+++ b/include/qemu-common.h
@@ -82,6 +82,18 @@ bool tcg_enabled(void);
void cpu_exec_init_all(void);
/**
+ * set_preferred_target_page_bits:
+ * @bits: number of bits needed to represent an address within the page
+ *
+ * Set the preferred target page size (the actual target page
+ * size may be smaller than any given CPU's preference).
+ * Returns true on success, false on failure (which can only happen
+ * if this is called after the system has already finalized its
+ * choice of page size and the requested page size is smaller than that).
+ */
+bool set_preferred_target_page_bits(int bits);
+
+/**
* Sends a (part of) iovec down a socket, yielding when the socket is full, or
* Receives data into a (part of) iovec from a socket,
* yielding when there is no data in the socket.