Re: [RFC PATCH 6/7] linux-user: Handle SIGSEGV/SIGBUS in host_to_target_siginfo_noswap

[Warner Losh]

On Mon, Sep 13, 2021 at 4:05 PM Richard Henderson <richard.henderson@linaro.org> wrote:

Remap the faulting address from the host address space into
the guest address space.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 linux-user/signal.c | 9 +++++++++
 1 file changed, 9 insertions(+)

Reviewed-by: Warner Losh <imp@bsdimp.com>

If I'm understanding this right, the FreeBSD code in the bsd-user fork won't be affected by this change.

(or conversely, it's so far behind the linux stuff that it will need to be completely

revamped).

Warner

 

diff --git a/linux-user/signal.c b/linux-user/signal.c
index a8faea6f09..73c0f9066b 100644
--- a/linux-user/signal.c
+++ b/linux-user/signal.c
@@ -405,6 +405,15 @@ static inline void host_to_target_siginfo_noswap(target_siginfo_t *tinfo,
             tinfo->_sifields._sigpoll._fd = info->si_fd;
             si_type = QEMU_SI_POLL;
             break;
+        case TARGET_SIGSEGV:
+        case TARGET_SIGBUS:
+            /*
+             * Remap the host address into the target space.
+             * Even an invalid guest address is still valid for a fault.
+             */
+            tinfo->_sifields._sigfault._addr = h2g_nocheck(info->si_addr);
+            si_type = QEMU_SI_FAULT;
+            break;
         default:
             /* Assume a sigqueue()/mq_notify()/rt_sigqueueinfo() source. */
             tinfo->_sifields._rt._pid = info->si_pid;
--
2.25.1