From: David Gibson <david@gibson.dropbear.id.au>
To: Greg Kurz <gkurz@linux.vnet.ibm.com>
Cc: qemu-devel@nongnu.org, Paolo Bonzini <pbonzini@redhat.com>,
qemu-ppc@nongnu.org, Alexander Graf <agraf@suse.de>,
Anton Blanchard <anton@samba.org>
Subject: Re: [Qemu-devel] [PATCH 5/7] target-ppc: gdbstub: fix altivec registers for little-endian guests
Date: Mon, 18 Jan 2016 13:25:19 +1100 [thread overview]
Message-ID: <20160118022519.GH9301@voom.fritz.box> (raw)
In-Reply-To: <20160115150038.17358.21849.stgit@bahia.huguette.org>
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On Fri, Jan 15, 2016 at 04:00:38PM +0100, Greg Kurz wrote:
> Altivec registers are 128-bit wide. They are stored in memory as two
> 64-bit values that must be byteswapped when the guest is little-endian.
> Let's reuse the ppc_maybe_bswap_register() helper for this.
>
> We also need to fix the ordering of the 64-bit elements according to
> the target endianness, for both system and user mode.
>
> Signed-off-by: Greg Kurz <gkurz@linux.vnet.ibm.com>
What bothers me about this is that avr_need_swap() now depends on both
host and guest endianness. However the VSCR and VRSAVE swap - like
the swaps for GPRs and FPRs - uses ppc_maybe_bswap_register() which
depends only on guest endianness.
Why does altivec depend on the host endianness?
> ---
> target-ppc/translate_init.c | 12 ++++++++++--
> 1 file changed, 10 insertions(+), 2 deletions(-)
>
> diff --git a/target-ppc/translate_init.c b/target-ppc/translate_init.c
> index 18e9e561561f..80d53e4dcf5a 100644
> --- a/target-ppc/translate_init.c
> +++ b/target-ppc/translate_init.c
> @@ -8754,9 +8754,9 @@ static void dump_ppc_insns (CPUPPCState *env)
> static bool avr_need_swap(CPUPPCState *env)
> {
> #ifdef HOST_WORDS_BIGENDIAN
> - return false;
> + return msr_le;
> #else
> - return true;
> + return !msr_le;
> #endif
> }
>
> @@ -8800,14 +8800,18 @@ static int gdb_get_avr_reg(CPUPPCState *env, uint8_t *mem_buf, int n)
> stq_p(mem_buf, env->avr[n].u64[1]);
> stq_p(mem_buf+8, env->avr[n].u64[0]);
> }
> + ppc_maybe_bswap_register(env, mem_buf, 8);
> + ppc_maybe_bswap_register(env, mem_buf + 8, 8);
> return 16;
> }
> if (n == 32) {
> stl_p(mem_buf, env->vscr);
> + ppc_maybe_bswap_register(env, mem_buf, 4);
> return 4;
> }
> if (n == 33) {
> stl_p(mem_buf, (uint32_t)env->spr[SPR_VRSAVE]);
> + ppc_maybe_bswap_register(env, mem_buf, 4);
> return 4;
> }
> return 0;
> @@ -8816,6 +8820,8 @@ static int gdb_get_avr_reg(CPUPPCState *env, uint8_t *mem_buf, int n)
> static int gdb_set_avr_reg(CPUPPCState *env, uint8_t *mem_buf, int n)
> {
> if (n < 32) {
> + ppc_maybe_bswap_register(env, mem_buf, 8);
> + ppc_maybe_bswap_register(env, mem_buf + 8, 8);
> if (!avr_need_swap(env)) {
> env->avr[n].u64[0] = ldq_p(mem_buf);
> env->avr[n].u64[1] = ldq_p(mem_buf+8);
> @@ -8826,10 +8832,12 @@ static int gdb_set_avr_reg(CPUPPCState *env, uint8_t *mem_buf, int n)
> return 16;
> }
> if (n == 32) {
> + ppc_maybe_bswap_register(env, mem_buf, 4);
> env->vscr = ldl_p(mem_buf);
> return 4;
> }
> if (n == 33) {
> + ppc_maybe_bswap_register(env, mem_buf, 4);
> env->spr[SPR_VRSAVE] = (target_ulong)ldl_p(mem_buf);
> return 4;
> }
>
--
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
http://www.ozlabs.org/~dgibson
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next prev parent reply other threads:[~2016-01-18 2:27 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-01-15 15:00 [Qemu-devel] [PATCH 0/7] target-ppc: gdbstub: endiannes fixes and VSX support Greg Kurz
2016-01-15 15:00 ` [Qemu-devel] [PATCH 1/7] target-ppc: kvm: fix floating point registers sync on little-endian hosts Greg Kurz
2016-01-18 2:16 ` David Gibson
2016-01-18 8:51 ` Greg Kurz
2016-01-19 0:55 ` David Gibson
2016-01-19 12:10 ` Greg Kurz
2016-01-15 15:00 ` [Qemu-devel] [PATCH 2/7] target-ppc: rename and export maybe_bswap_register() Greg Kurz
2016-01-15 15:00 ` [Qemu-devel] [PATCH 3/7] target-ppc: gdbstub: fix float registers for little-endian guests Greg Kurz
2016-01-15 15:00 ` [Qemu-devel] [PATCH 4/7] target-ppc: gdbstub: introduce avr_need_swap() Greg Kurz
2016-01-15 15:00 ` [Qemu-devel] [PATCH 5/7] target-ppc: gdbstub: fix altivec registers for little-endian guests Greg Kurz
2016-01-18 2:25 ` David Gibson [this message]
2016-01-19 9:59 ` Greg Kurz
2016-01-20 2:13 ` [Qemu-devel] [Qemu-ppc] " David Gibson
2016-01-20 7:55 ` Greg Kurz
2016-01-15 15:00 ` [Qemu-devel] [PATCH 6/7] target-ppc: gdbstub: fix spe " Greg Kurz
2016-01-15 15:00 ` [Qemu-devel] [PATCH 7/7] target-ppc: gdbstub: Add VSX support Greg Kurz
-- strict thread matches above, loose matches on Subject: below --
2015-12-18 10:18 [Qemu-devel] [PATCH 0/7] target-ppc: endian fixes for KVM and gdbstub Greg Kurz
2015-12-18 10:19 ` [Qemu-devel] [PATCH 5/7] target-ppc: gdbstub: fix altivec registers for little-endian guests Greg Kurz
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