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[PATCH 3/9] include/exec: Replace reserved_va with max_reserved_va
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From: |
Richard Henderson |
|
Subject: |
[PATCH 3/9] include/exec: Replace reserved_va with max_reserved_va |
|
Date: |
Sun, 5 Mar 2023 18:13:01 -0800 |
In addition to the rename, change the semantics to be the
last byte of the guest va, rather than the following byte.
This avoids some overflow conditions.
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
include/exec/cpu-all.h | 15 ++++++++++++---
linux-user/arm/target_cpu.h | 2 +-
bsd-user/main.c | 18 +++++++-----------
bsd-user/mmap.c | 12 ++++++------
bsd-user/signal.c | 4 ++--
linux-user/elfload.c | 36 ++++++++++++++++++------------------
linux-user/main.c | 36 ++++++++++++++++--------------------
linux-user/mmap.c | 20 ++++++++++----------
linux-user/signal.c | 4 ++--
target/arm/cpu.c | 2 +-
10 files changed, 75 insertions(+), 74 deletions(-)
diff --git a/include/exec/cpu-all.h b/include/exec/cpu-all.h
index 2eb1176538..7ef6b9a94d 100644
--- a/include/exec/cpu-all.h
+++ b/include/exec/cpu-all.h
@@ -152,12 +152,21 @@ static inline void tswap64s(uint64_t *s)
*/
extern uintptr_t guest_base;
extern bool have_guest_base;
-extern unsigned long reserved_va;
+
+/*
+ * If non-zero, the guest virtual address space is a contiguous subset
+ * of the host virtual address space, i.e. '-R reserved-va' is in effect
+ * either from the command-line or by default. The value is the last
+ * byte of the guest address space e.g. UINT32_MAX.
+ *
+ * If zero, the host and guest virtual address spaces are intermingled.
+ */
+extern unsigned long max_reserved_va;
/*
* Limit the guest addresses as best we can.
*
- * When not using -R reserved_va, we cannot really limit the guest
+ * When not using -R <reserved-va>, we cannot really limit the guest
* to less address space than the host. For 32-bit guests, this
* acts as a sanity check that we're not giving the guest an address
* that it cannot even represent. For 64-bit guests... the address
@@ -171,7 +180,7 @@ extern unsigned long reserved_va;
#define GUEST_ADDR_MAX_ \
((MIN_CONST(TARGET_VIRT_ADDR_SPACE_BITS, TARGET_ABI_BITS) <= 32) ? \
UINT32_MAX : ~0ul)
-#define GUEST_ADDR_MAX (reserved_va ? reserved_va - 1 : GUEST_ADDR_MAX_)
+#define GUEST_ADDR_MAX (max_reserved_va ? : GUEST_ADDR_MAX_)
#else
diff --git a/linux-user/arm/target_cpu.h b/linux-user/arm/target_cpu.h
index 89ba274cfc..f6383a7cd1 100644
--- a/linux-user/arm/target_cpu.h
+++ b/linux-user/arm/target_cpu.h
@@ -30,7 +30,7 @@ static inline unsigned long arm_max_reserved_va(CPUState *cs)
* the high addresses. Restrict linux-user to the
* cached write-back RAM in the system map.
*/
- return 0x80000000ul;
+ return 0x7ffffffful;
} else {
/*
* We need to be able to map the commpage.
diff --git a/bsd-user/main.c b/bsd-user/main.c
index 41290e16f9..de413bd1d2 100644
--- a/bsd-user/main.c
+++ b/bsd-user/main.c
@@ -67,16 +67,12 @@ bool have_guest_base;
# if HOST_LONG_BITS > TARGET_VIRT_ADDR_SPACE_BITS
# if TARGET_VIRT_ADDR_SPACE_BITS == 32 && \
(TARGET_LONG_BITS == 32 || defined(TARGET_ABI32))
-/*
- * There are a number of places where we assign reserved_va to a variable
- * of type abi_ulong and expect it to fit. Avoid the last page.
- */
-# define MAX_RESERVED_VA (0xfffffffful & TARGET_PAGE_MASK)
+# define MAX_RESERVED_VA 0xfffffffful
# else
-# define MAX_RESERVED_VA (1ul << TARGET_VIRT_ADDR_SPACE_BITS)
+# define MAX_RESERVED_VA ((1ul << TARGET_VIRT_ADDR_SPACE_BITS) - 1)
# endif
# else
-# define MAX_RESERVED_VA 0
+# define MAX_RESERVED_VA (-1ul)
# endif
#endif
@@ -86,9 +82,9 @@ bool have_guest_base;
* if directed by the command-line option, but not by default.
*/
#if HOST_LONG_BITS == 64 && TARGET_VIRT_ADDR_SPACE_BITS <= 32
-unsigned long reserved_va = MAX_RESERVED_VA;
+unsigned long max_reserved_va = MAX_RESERVED_VA;
#else
-unsigned long reserved_va;
+unsigned long max_reserved_va;
#endif
static const char *interp_prefix = CONFIG_QEMU_INTERP_PREFIX;
@@ -464,8 +460,8 @@ int main(int argc, char **argv)
target_environ = envlist_to_environ(envlist, NULL);
envlist_free(envlist);
- if (reserved_va) {
- mmap_next_start = reserved_va;
+ if (max_reserved_va) {
+ mmap_next_start = max_reserved_va;
}
{
diff --git a/bsd-user/mmap.c b/bsd-user/mmap.c
index d6c5a344c9..e9a330d599 100644
--- a/bsd-user/mmap.c
+++ b/bsd-user/mmap.c
@@ -227,14 +227,14 @@ static abi_ulong mmap_find_vma_reserved(abi_ulong start,
abi_ulong size,
int prot;
int looped = 0;
- if (size > reserved_va) {
+ if (size > max_reserved_va) {
return (abi_ulong)-1;
}
size = HOST_PAGE_ALIGN(size) + alignment;
end_addr = start + size;
- if (end_addr > reserved_va) {
- end_addr = reserved_va;
+ if (end_addr > max_reserved_va) {
+ end_addr = max_reserved_va + 1;
}
addr = end_addr - qemu_host_page_size;
@@ -243,7 +243,7 @@ static abi_ulong mmap_find_vma_reserved(abi_ulong start,
abi_ulong size,
if (looped) {
return (abi_ulong)-1;
}
- end_addr = reserved_va;
+ end_addr = max_reserved_va + 1;
addr = end_addr - qemu_host_page_size;
looped = 1;
continue;
@@ -291,7 +291,7 @@ static abi_ulong mmap_find_vma_aligned(abi_ulong start,
abi_ulong size,
size = HOST_PAGE_ALIGN(size);
- if (reserved_va) {
+ if (max_reserved_va) {
return mmap_find_vma_reserved(start, size,
(alignment != 0 ? 1 << alignment : 0));
}
@@ -759,7 +759,7 @@ int target_munmap(abi_ulong start, abi_ulong len)
ret = 0;
/* unmap what we can */
if (real_start < real_end) {
- if (reserved_va) {
+ if (max_reserved_va) {
mmap_reserve(real_start, real_end - real_start);
} else {
ret = munmap(g2h_untagged(real_start), real_end - real_start);
diff --git a/bsd-user/signal.c b/bsd-user/signal.c
index 58a5386395..be12568f6c 100644
--- a/bsd-user/signal.c
+++ b/bsd-user/signal.c
@@ -492,7 +492,7 @@ static void host_signal_handler(int host_sig, siginfo_t
*info, void *puc)
/*
* Convert forcefully to guest address space: addresses outside
- * reserved_va are still valid to report via SEGV_MAPERR.
+ * max_reserved_va are still valid to report via SEGV_MAPERR.
*/
guest_addr = h2g_nocheck(host_addr);
@@ -512,7 +512,7 @@ static void host_signal_handler(int host_sig, siginfo_t
*info, void *puc)
}
/*
- * With reserved_va, the whole address space is PROT_NONE,
+ * With max_reserved_va, the whole address space is PROT_NONE,
* which means that we may get ACCERR when we want MAPERR.
*/
if (page_get_flags(guest_addr) & PAGE_VALID) {
diff --git a/linux-user/elfload.c b/linux-user/elfload.c
index 5928c14dfc..104c13ec77 100644
--- a/linux-user/elfload.c
+++ b/linux-user/elfload.c
@@ -204,10 +204,10 @@ static bool init_guest_commpage(void)
* The vsyscall page is at a high negative address aka kernel space,
* which means that we cannot actually allocate it with target_mmap.
* We still should be able to use page_set_flags, unless the user
- * has specified -R reserved_va, which would trigger an assert().
+ * has specified -R <reserved-va>, which would trigger an assert().
*/
- if (reserved_va != 0 &&
- TARGET_VSYSCALL_PAGE + TARGET_PAGE_SIZE >= reserved_va) {
+ if (max_reserved_va != 0 &&
+ TARGET_VSYSCALL_PAGE + TARGET_PAGE_SIZE - 1 >= max_reserved_va) {
error_report("Cannot allocate vsyscall page");
exit(EXIT_FAILURE);
}
@@ -2484,11 +2484,11 @@ static void pgb_have_guest_base(const char *image_name,
abi_ulong guest_loaddr,
}
/* Sanity check the guest binary. */
- if (reserved_va) {
- if (guest_hiaddr > reserved_va) {
+ if (max_reserved_va) {
+ if (guest_hiaddr - 1 > max_reserved_va) {
error_report("%s: requires more than reserved virtual "
"address space (0x%" PRIx64 " > 0x%lx)",
- image_name, (uint64_t)guest_hiaddr, reserved_va);
+ image_name, (uint64_t)guest_hiaddr - 1,
max_reserved_va);
exit(EXIT_FAILURE);
}
} else {
@@ -2503,16 +2503,16 @@ static void pgb_have_guest_base(const char *image_name,
abi_ulong guest_loaddr,
}
/*
- * Expand the allocation to the entire reserved_va.
+ * Expand the allocation to the entire max_reserved_va.
* Exclude the mmap_min_addr hole.
*/
- if (reserved_va) {
+ if (max_reserved_va) {
guest_loaddr = (guest_base >= mmap_min_addr ? 0
: mmap_min_addr - guest_base);
- guest_hiaddr = reserved_va;
+ guest_hiaddr = max_reserved_va + 1;
}
- /* Reserve the address space for the binary, or reserved_va. */
+ /* Reserve the address space for the binary, or max_reserved_va. */
test = g2h_untagged(guest_loaddr);
addr = mmap(test, guest_hiaddr - guest_loaddr, PROT_NONE, flags, -1, 0);
if (test != addr) {
@@ -2716,7 +2716,7 @@ static void pgb_dynamic(const char *image_name, long
align)
if (HI_COMMPAGE) {
uintptr_t addr, commpage;
- /* 64-bit hosts should have used reserved_va. */
+ /* 64-bit hosts should have used max_reserved_va. */
assert(sizeof(uintptr_t) == 4);
/*
@@ -2736,15 +2736,15 @@ static void pgb_reserved_va(const char *image_name,
abi_ulong guest_loaddr,
int flags = MAP_ANONYMOUS | MAP_PRIVATE | MAP_NORESERVE;
void *addr, *test;
- if (guest_hiaddr > reserved_va) {
+ if (guest_hiaddr - 1 > max_reserved_va) {
error_report("%s: requires more than reserved virtual "
"address space (0x%" PRIx64 " > 0x%lx)",
- image_name, (uint64_t)guest_hiaddr, reserved_va);
+ image_name, (uint64_t)guest_hiaddr - 1, max_reserved_va);
exit(EXIT_FAILURE);
}
/* Widen the "image" to the entire reserved address space. */
- pgb_static(image_name, 0, reserved_va, align);
+ pgb_static(image_name, 0, max_reserved_va + 1, align);
/* osdep.h defines this as 0 if it's missing */
flags |= MAP_FIXED_NOREPLACE;
@@ -2752,17 +2752,17 @@ static void pgb_reserved_va(const char *image_name,
abi_ulong guest_loaddr,
/* Reserve the memory on the host. */
assert(guest_base != 0);
test = g2h_untagged(0);
- addr = mmap(test, reserved_va, PROT_NONE, flags, -1, 0);
+ addr = mmap(test, max_reserved_va + 1, PROT_NONE, flags, -1, 0);
if (addr == MAP_FAILED || addr != test) {
error_report("Unable to reserve 0x%lx bytes of virtual address "
"space at %p (%s) for use as guest address space (check
your "
"virtual memory ulimit setting, min_mmap_addr or reserve
less "
- "using -R option)", reserved_va, test, strerror(errno));
+ "using -R option)", max_reserved_va + 1, test,
strerror(errno));
exit(EXIT_FAILURE);
}
qemu_log_mask(CPU_LOG_PAGE, "%s: base @ %p for %lu bytes\n",
- __func__, addr, reserved_va);
+ __func__, addr, max_reserved_va + 1);
}
void probe_guest_base(const char *image_name, abi_ulong guest_loaddr,
@@ -2773,7 +2773,7 @@ void probe_guest_base(const char *image_name, abi_ulong
guest_loaddr,
if (have_guest_base) {
pgb_have_guest_base(image_name, guest_loaddr, guest_hiaddr, align);
- } else if (reserved_va) {
+ } else if (max_reserved_va) {
pgb_reserved_va(image_name, guest_loaddr, guest_hiaddr, align);
} else if (guest_loaddr) {
pgb_static(image_name, guest_loaddr, guest_hiaddr, align);
diff --git a/linux-user/main.c b/linux-user/main.c
index 5fcaddffc2..f5731a1157 100644
--- a/linux-user/main.c
+++ b/linux-user/main.c
@@ -107,18 +107,16 @@ static const char *last_log_filename;
# if HOST_LONG_BITS > TARGET_VIRT_ADDR_SPACE_BITS
# if TARGET_VIRT_ADDR_SPACE_BITS == 32 && \
(TARGET_LONG_BITS == 32 || defined(TARGET_ABI32))
-/* There are a number of places where we assign reserved_va to a variable
- of type abi_ulong and expect it to fit. Avoid the last page. */
-# define MAX_RESERVED_VA(CPU) (0xfffffffful & TARGET_PAGE_MASK)
+# define MAX_RESERVED_VA(CPU) 0xfffffffful
# else
-# define MAX_RESERVED_VA(CPU) (1ul << TARGET_VIRT_ADDR_SPACE_BITS)
+# define MAX_RESERVED_VA(CPU) ((1ul << TARGET_VIRT_ADDR_SPACE_BITS) - 1)
# endif
# else
-# define MAX_RESERVED_VA(CPU) 0
+# define MAX_RESERVED_VA(CPU) (-1ul)
# endif
#endif
-unsigned long reserved_va;
+unsigned long max_reserved_va;
static void usage(int exitcode);
@@ -369,7 +367,8 @@ static void handle_arg_reserved_va(const char *arg)
{
char *p;
int shift = 0;
- reserved_va = strtoul(arg, &p, 0);
+
+ max_reserved_va = strtoul(arg, &p, 0);
switch (*p) {
case 'k':
case 'K':
@@ -383,10 +382,10 @@ static void handle_arg_reserved_va(const char *arg)
break;
}
if (shift) {
- unsigned long unshifted = reserved_va;
+ unsigned long unshifted = max_reserved_va;
p++;
- reserved_va <<= shift;
- if (reserved_va >> shift != unshifted) {
+ max_reserved_va <<= shift;
+ if (max_reserved_va >> shift != unshifted) {
fprintf(stderr, "Reserved virtual address too big\n");
exit(EXIT_FAILURE);
}
@@ -395,16 +394,17 @@ static void handle_arg_reserved_va(const char *arg)
fprintf(stderr, "Unrecognised -R size suffix '%s'\n", p);
exit(EXIT_FAILURE);
}
- if (reserved_va == 0) {
+ if (max_reserved_va == 0) {
fprintf(stderr, "Invalid -R size value 0\n");
exit(EXIT_FAILURE);
}
/* Must be aligned with the host page size as it is used with mmap. */
- if (reserved_va & qemu_host_page_mask) {
+ if (max_reserved_va & qemu_host_page_mask) {
fprintf(stderr, "Invalid -R size value %lu: must be aligned mod %lu\n",
- reserved_va, qemu_host_page_size);
+ max_reserved_va, qemu_host_page_size);
exit(EXIT_FAILURE);
}
+ max_reserved_va--;
}
static void handle_arg_singlestep(const char *arg)
@@ -787,17 +787,13 @@ int main(int argc, char **argv, char **envp)
* not by default.
*/
local_max_va = MAX_RESERVED_VA(cpu);
- if (reserved_va != 0) {
- if (local_max_va && reserved_va > local_max_va) {
+ if (max_reserved_va != 0) {
+ if (max_reserved_va > local_max_va) {
fprintf(stderr, "Reserved virtual address too big\n");
exit(EXIT_FAILURE);
}
} else if (HOST_LONG_BITS == 64 && TARGET_VIRT_ADDR_SPACE_BITS <= 32) {
- /*
- * reserved_va must be aligned with the host page size
- * as it is used with mmap()
- */
- reserved_va = local_max_va & qemu_host_page_mask;
+ max_reserved_va = local_max_va;
}
{
diff --git a/linux-user/mmap.c b/linux-user/mmap.c
index 28135c9e6a..547be8dff6 100644
--- a/linux-user/mmap.c
+++ b/linux-user/mmap.c
@@ -274,16 +274,16 @@ static abi_ulong mmap_find_vma_reserved(abi_ulong start,
abi_ulong size,
int prot;
bool looped = false;
- if (size > reserved_va) {
+ if (size > max_reserved_va) {
return (abi_ulong)-1;
}
/* Note that start and size have already been aligned by mmap_find_vma. */
end_addr = start + size;
- if (start > reserved_va - size) {
+ if (start > max_reserved_va + 1 - size) {
/* Start at the top of the address space. */
- end_addr = ((reserved_va - size) & -align) + size;
+ end_addr = ((max_reserved_va + 1 - size) & -align) + size;
looped = true;
}
@@ -297,7 +297,7 @@ static abi_ulong mmap_find_vma_reserved(abi_ulong start,
abi_ulong size,
return (abi_ulong)-1;
}
/* Re-start at the top of the address space. */
- addr = end_addr = ((reserved_va - size) & -align) + size;
+ addr = end_addr = ((max_reserved_va + 1 - size) & -align) + size;
looped = true;
} else {
prot = page_get_flags(addr);
@@ -339,7 +339,7 @@ abi_ulong mmap_find_vma(abi_ulong start, abi_ulong size,
abi_ulong align)
size = HOST_PAGE_ALIGN(size);
- if (reserved_va) {
+ if (max_reserved_va) {
return mmap_find_vma_reserved(start, size, align);
}
@@ -755,7 +755,7 @@ int target_munmap(abi_ulong start, abi_ulong len)
ret = 0;
/* unmap what we can */
if (real_start < real_end) {
- if (reserved_va) {
+ if (max_reserved_va) {
mmap_reserve(real_start, real_end - real_start);
} else {
ret = munmap(g2h_untagged(real_start), real_end - real_start);
@@ -791,7 +791,7 @@ abi_long target_mremap(abi_ulong old_addr, abi_ulong
old_size,
host_addr = mremap(g2h_untagged(old_addr), old_size, new_size,
flags, g2h_untagged(new_addr));
- if (reserved_va && host_addr != MAP_FAILED) {
+ if (max_reserved_va && host_addr != MAP_FAILED) {
/* If new and old addresses overlap then the above mremap will
already have failed with EINVAL. */
mmap_reserve(old_addr, old_size);
@@ -808,13 +808,13 @@ abi_long target_mremap(abi_ulong old_addr, abi_ulong
old_size,
host_addr = mremap(g2h_untagged(old_addr), old_size, new_size,
flags | MREMAP_FIXED,
g2h_untagged(mmap_start));
- if (reserved_va) {
+ if (max_reserved_va) {
mmap_reserve(old_addr, old_size);
}
}
} else {
int prot = 0;
- if (reserved_va && old_size < new_size) {
+ if (max_reserved_va && old_size < new_size) {
abi_ulong addr;
for (addr = old_addr + old_size;
addr < old_addr + new_size;
@@ -834,7 +834,7 @@ abi_long target_mremap(abi_ulong old_addr, abi_ulong
old_size,
new_size, old_size, flags);
errno = ENOMEM;
host_addr = MAP_FAILED;
- } else if (reserved_va && old_size > new_size) {
+ } else if (max_reserved_va && old_size > new_size) {
mmap_reserve(old_addr + old_size, old_size - new_size);
}
}
diff --git a/linux-user/signal.c b/linux-user/signal.c
index 098f3a787d..f40b0a616a 100644
--- a/linux-user/signal.c
+++ b/linux-user/signal.c
@@ -808,7 +808,7 @@ static void host_signal_handler(int host_sig, siginfo_t
*info, void *puc)
/*
* Convert forcefully to guest address space: addresses outside
- * reserved_va are still valid to report via SEGV_MAPERR.
+ * max_reserved_va are still valid to report via SEGV_MAPERR.
*/
guest_addr = h2g_nocheck(host_addr);
@@ -827,7 +827,7 @@ static void host_signal_handler(int host_sig, siginfo_t
*info, void *puc)
}
/*
- * With reserved_va, the whole address space is PROT_NONE,
+ * With max_reserved_va, the whole address space is PROT_NONE,
* which means that we may get ACCERR when we want MAPERR.
*/
if (page_get_flags(guest_addr) & PAGE_VALID) {
diff --git a/target/arm/cpu.c b/target/arm/cpu.c
index 5182ed0c91..b9cd0d3e33 100644
--- a/target/arm/cpu.c
+++ b/target/arm/cpu.c
@@ -264,7 +264,7 @@ static void arm_cpu_reset_hold(Object *obj)
}
}
/*
- * Enable 48-bit address space (TODO: take reserved_va into account).
+ * Enable 48-bit address space (TODO: take max_reserved_va into
account).
* Enable TBI0 but not TBI1.
* Note that this must match useronly_clean_ptr.
*/
--
2.34.1
- Re: [PATCH 1/9] linux-user: Diagnose incorrect -R size, (continued)
- Re: [PATCH 1/9] linux-user: Diagnose incorrect -R size, Richard Henderson, 2023/03/06
- Re: [PATCH 1/9] linux-user: Diagnose incorrect -R size, Peter Maydell, 2023/03/07
- Re: [PATCH 1/9] linux-user: Diagnose incorrect -R size, Peter Maydell, 2023/03/07
- Re: [PATCH 1/9] linux-user: Diagnose incorrect -R size, Richard Henderson, 2023/03/17
- Re: [PATCH 1/9] linux-user: Diagnose incorrect -R size, Peter Maydell, 2023/03/17
- Re: [PATCH 1/9] linux-user: Diagnose incorrect -R size, Peter Maydell, 2023/03/17
[PATCH 2/9] linux-user: Rename max_reserved_va in main, Richard Henderson, 2023/03/05
[PATCH 5/9] accel/tcg: Pass last not end to page_reset_target_data, Richard Henderson, 2023/03/05
[PATCH 3/9] include/exec: Replace reserved_va with max_reserved_va,
Richard Henderson <=
[PATCH 6/9] accel/tcg: Pass last not end to PAGE_FOR_EACH_TB, Richard Henderson, 2023/03/05
[PATCH 7/9] accel/tcg: Pass last not end to page_collection_lock, Richard Henderson, 2023/03/05
[PATCH 4/9] accel/tcg: Pass last not end to page_set_flags, Richard Henderson, 2023/03/05
[PATCH 9/9] accel/tcg: Pass last not end to tb_invalidate_phys_range, Richard Henderson, 2023/03/05
[PATCH 8/9] accel/tcg: Pass last not end to tb_invalidate_phys_page_range__locked, Richard Henderson, 2023/03/05
Re: [PATCH 0/9] accel/tcg: Fix page_set_flags and related [#1528], Joel Stanley, 2023/03/06