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authorRichard Henderson <richard.henderson@linaro.org>2020-05-13 18:51:30 +0100
committerAlex Bennée <alex.bennee@linaro.org>2020-05-15 15:25:16 +0100
commit7d8cbbabcb1234ffba9a946083073a5e01cdc020 (patch)
treedba9b449c5970e0757f433d0333d77b87ba9e046 /accel
parente307c192ff95c7c30d1c2fa02409686d450c1ccd (diff)
accel/tcg: Relax va restrictions on 64-bit guests
We cannot at present limit a 64-bit guest to a virtual address space smaller than the host. It will mostly work to ignore this limitation, except if the guest uses high bits of the address space for tags. But it will certainly work better, as presently we can wind up failing to allocate the guest stack. Widen our user-only page tree to the host or abi pointer width. Remove the workaround for this problem from target/alpha. Always validate guest addresses vs reserved_va, as there we control allocation ourselves. Signed-off-by: Richard Henderson <richard.henderson@linaro.org> Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Message-Id: <20200513175134.19619-7-alex.bennee@linaro.org>
Diffstat (limited to 'accel')
-rw-r--r--accel/tcg/translate-all.c15
1 files changed, 9 insertions, 6 deletions
diff --git a/accel/tcg/translate-all.c b/accel/tcg/translate-all.c
index 9924e66d1f..e4f703a7e6 100644
--- a/accel/tcg/translate-all.c
+++ b/accel/tcg/translate-all.c
@@ -173,8 +173,13 @@ struct page_collection {
#define TB_FOR_EACH_JMP(head_tb, tb, n) \
TB_FOR_EACH_TAGGED((head_tb)->jmp_list_head, tb, n, jmp_list_next)
-/* In system mode we want L1_MAP to be based on ram offsets,
- while in user mode we want it to be based on virtual addresses. */
+/*
+ * In system mode we want L1_MAP to be based on ram offsets,
+ * while in user mode we want it to be based on virtual addresses.
+ *
+ * TODO: For user mode, see the caveat re host vs guest virtual
+ * address spaces near GUEST_ADDR_MAX.
+ */
#if !defined(CONFIG_USER_ONLY)
#if HOST_LONG_BITS < TARGET_PHYS_ADDR_SPACE_BITS
# define L1_MAP_ADDR_SPACE_BITS HOST_LONG_BITS
@@ -182,7 +187,7 @@ struct page_collection {
# define L1_MAP_ADDR_SPACE_BITS TARGET_PHYS_ADDR_SPACE_BITS
#endif
#else
-# define L1_MAP_ADDR_SPACE_BITS TARGET_VIRT_ADDR_SPACE_BITS
+# define L1_MAP_ADDR_SPACE_BITS MIN(HOST_LONG_BITS, TARGET_ABI_BITS)
#endif
/* Size of the L2 (and L3, etc) page tables. */
@@ -2497,9 +2502,7 @@ void page_set_flags(target_ulong start, target_ulong end, int flags)
/* This function should never be called with addresses outside the
guest address space. If this assert fires, it probably indicates
a missing call to h2g_valid. */
-#if TARGET_ABI_BITS > L1_MAP_ADDR_SPACE_BITS
- assert(end <= ((target_ulong)1 << L1_MAP_ADDR_SPACE_BITS));
-#endif
+ assert(end - 1 <= GUEST_ADDR_MAX);
assert(start < end);
assert_memory_lock();