| Message ID | 20211010174401.141339-5-richard.henderson@linaro.org |
|---|---|
| State | Superseded |
| Headers | show |
| Series | tcg: support 32-bit guest addresses as signed | expand |
On 10/10/21 19:43, Richard Henderson wrote: > While the host may prefer to treat 32-bit addresses as signed, > there are edge cases of guests that cannot be implemented with > addresses 0x7fff_ffff and 0x8000_0000 being non-consecutive. > > Therefore, default to guest_base_signed_addr32 false, and allow > probe_guest_base to determine whether it is possible to set it > to true. A tcg backend which sets TCG_TARGET_SIGNED_ADDR32 will > have to cope with either setting for user-only. > > Signed-off-by: Richard Henderson <richard.henderson@linaro.org> > --- > include/exec/cpu-all.h | 16 ++++++++++++++++ > include/exec/cpu_ldst.h | 3 ++- > bsd-user/main.c | 4 ++++ > linux-user/main.c | 3 +++ > 4 files changed, 25 insertions(+), 1 deletion(-) > > diff --git a/include/exec/cpu-all.h b/include/exec/cpu-all.h > index 32cfb634c6..80b5e17329 100644 > --- a/include/exec/cpu-all.h > +++ b/include/exec/cpu-all.h > @@ -146,6 +146,7 @@ static inline void tswap64s(uint64_t *s) > > #if defined(CONFIG_USER_ONLY) > #include "exec/user/abitypes.h" > +#include "tcg-target-sa32.h" Unrelated but this header could be simplified by moving this block to a new header such "exec/user/address.h". > > /* On some host systems the guest address space is reserved on the host. > * This allows the guest address space to be offset to a convenient location. > @@ -154,6 +155,21 @@ extern uintptr_t guest_base; > extern bool have_guest_base; > extern unsigned long reserved_va; > > +#if TCG_TARGET_SIGNED_ADDR32 && TARGET_LONG_BITS == 32 > +extern bool guest_base_signed_addr32; > +#else > +#define guest_base_signed_addr32 false > +#endif > + > +static inline void set_guest_base_signed_addr32(void) > +{ > +#ifdef guest_base_signed_addr32 > + qemu_build_not_reached(); > +#else > + guest_base_signed_addr32 = true; > +#endif > +} > + > /* > * Limit the guest addresses as best we can. > * Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
On Mon, Oct 11, 2021 at 3:52 AM Richard Henderson <richard.henderson@linaro.org> wrote: > > While the host may prefer to treat 32-bit addresses as signed, > there are edge cases of guests that cannot be implemented with > addresses 0x7fff_ffff and 0x8000_0000 being non-consecutive. > > Therefore, default to guest_base_signed_addr32 false, and allow > probe_guest_base to determine whether it is possible to set it > to true. A tcg backend which sets TCG_TARGET_SIGNED_ADDR32 will > have to cope with either setting for user-only. > > Signed-off-by: Richard Henderson <richard.henderson@linaro.org> Reviewed-by: Alistair Francis <alistair.francis@wdc.com> Alistair
diff --git a/include/exec/cpu-all.h b/include/exec/cpu-all.h index 32cfb634c6..80b5e17329 100644 --- a/include/exec/cpu-all.h +++ b/include/exec/cpu-all.h @@ -146,6 +146,7 @@ static inline void tswap64s(uint64_t *s) #if defined(CONFIG_USER_ONLY) #include "exec/user/abitypes.h" +#include "tcg-target-sa32.h" /* On some host systems the guest address space is reserved on the host. * This allows the guest address space to be offset to a convenient location. @@ -154,6 +155,21 @@ extern uintptr_t guest_base; extern bool have_guest_base; extern unsigned long reserved_va; +#if TCG_TARGET_SIGNED_ADDR32 && TARGET_LONG_BITS == 32 +extern bool guest_base_signed_addr32; +#else +#define guest_base_signed_addr32 false +#endif + +static inline void set_guest_base_signed_addr32(void) +{ +#ifdef guest_base_signed_addr32 + qemu_build_not_reached(); +#else + guest_base_signed_addr32 = true; +#endif +} + /* * Limit the guest addresses as best we can. * diff --git a/include/exec/cpu_ldst.h b/include/exec/cpu_ldst.h index ce6ce82618..db760ff5c2 100644 --- a/include/exec/cpu_ldst.h +++ b/include/exec/cpu_ldst.h @@ -79,7 +79,8 @@ static inline abi_ptr cpu_untagged_addr(CPUState *cs, abi_ptr x) /* All direct uses of g2h and h2g need to go away for usermode softmmu. */ static inline void *g2h_untagged(abi_ptr x) { - return (void *)((uintptr_t)(x) + guest_base); + uintptr_t hx = guest_base_signed_addr32 ? (int32_t)x : (uintptr_t)x; + return (void *)(guest_base + hx); } static inline void *g2h(CPUState *cs, abi_ptr x) diff --git a/bsd-user/main.c b/bsd-user/main.c index 48643eeabc..4fef0520da 100644 --- a/bsd-user/main.c +++ b/bsd-user/main.c @@ -54,6 +54,10 @@ int singlestep; uintptr_t guest_base; bool have_guest_base; +#ifndef guest_base_signed_addr32 +bool guest_base_signed_addr32; +#endif + /* * When running 32-on-64 we should make sure we can fit all of the possible * guest address space into a contiguous chunk of virtual host memory. diff --git a/linux-user/main.c b/linux-user/main.c index 16def5215d..ed7a88c195 100644 --- a/linux-user/main.c +++ b/linux-user/main.c @@ -72,6 +72,9 @@ static const char *seed_optarg; unsigned long mmap_min_addr; uintptr_t guest_base; bool have_guest_base; +#ifndef guest_base_signed_addr32 +bool guest_base_signed_addr32; +#endif /* * Used to implement backwards-compatibility for the `-strace`, and
While the host may prefer to treat 32-bit addresses as signed, there are edge cases of guests that cannot be implemented with addresses 0x7fff_ffff and 0x8000_0000 being non-consecutive. Therefore, default to guest_base_signed_addr32 false, and allow probe_guest_base to determine whether it is possible to set it to true. A tcg backend which sets TCG_TARGET_SIGNED_ADDR32 will have to cope with either setting for user-only. Signed-off-by: Richard Henderson <richard.henderson@linaro.org> --- include/exec/cpu-all.h | 16 ++++++++++++++++ include/exec/cpu_ldst.h | 3 ++- bsd-user/main.c | 4 ++++ linux-user/main.c | 3 +++ 4 files changed, 25 insertions(+), 1 deletion(-) -- 2.25.1