From: Greg Kurz <gkurz@linux.vnet.ibm.com>
To: Alexander Graf <agraf@suse.de>,
David Gibson <david@gibson.dropbear.id.au>
Cc: Paolo Bonzini <pbonzini@redhat.com>,
qemu-ppc@nongnu.org, Anton Blanchard <anton@samba.org>,
qemu-devel@nongnu.org
Subject: [Qemu-devel] [PATCH 1/7] target-ppc: kvm: fix floating point registers sync on little-endian hosts
Date: Fri, 15 Jan 2016 16:00:12 +0100 [thread overview]
Message-ID: <20160115150012.17358.95155.stgit@bahia.huguette.org> (raw)
In-Reply-To: <20160115150005.17358.43294.stgit@bahia.huguette.org>
On VSX capable CPUs, the 32 FP registers are mapped to the high-bits
of the 32 first VSX registers. So if you have:
VSR31 = (uint128) 0x0102030405060708090a0b0c0d0e0f00
then
FPR31 = (uint64) 0x0102030405060708
The kernel stores the VSX registers in the fp_state struct following the
host endian element ordering.
On big-endian:
fp_state.fpr[31][0] = 0x0102030405060708
fp_state.fpr[31][1] = 0x090a0b0c0d0e0f00
On little-endian:
fp_state.fpr[31][0] = 0x090a0b0c0d0e0f00
fp_state.fpr[31][1] = 0x0102030405060708
The KVM_GET_ONE_REG and KVM_SET_ONE_REG ioctls preserve this ordering, but
QEMU considers it as big-endian and always copies element [0] to the
fpr[] array and element [1] to the vsr[] array. This does not work with
little-endian hosts, and you will get:
(qemu) p $f31
0x90a0b0c0d0e0f00
instead of:
(qemu) p $f31
0x102030405060708
This patch fixes the element ordering for little-endian hosts.
Signed-off-by: Greg Kurz <gkurz@linux.vnet.ibm.com>
---
target-ppc/kvm.c | 12 ++++++++++++
1 file changed, 12 insertions(+)
diff --git a/target-ppc/kvm.c b/target-ppc/kvm.c
index 9940a9046220..45249990bda1 100644
--- a/target-ppc/kvm.c
+++ b/target-ppc/kvm.c
@@ -650,8 +650,13 @@ static int kvm_put_fp(CPUState *cs)
for (i = 0; i < 32; i++) {
uint64_t vsr[2];
+#ifdef HOST_WORDS_BIGENDIAN
vsr[0] = float64_val(env->fpr[i]);
vsr[1] = env->vsr[i];
+#else
+ vsr[0] = env->vsr[i];
+ vsr[1] = float64_val(env->fpr[i]);
+#endif
reg.addr = (uintptr_t) &vsr;
reg.id = vsx ? KVM_REG_PPC_VSR(i) : KVM_REG_PPC_FPR(i);
@@ -721,10 +726,17 @@ static int kvm_get_fp(CPUState *cs)
vsx ? "VSR" : "FPR", i, strerror(errno));
return ret;
} else {
+#ifdef HOST_WORDS_BIGENDIAN
env->fpr[i] = vsr[0];
if (vsx) {
env->vsr[i] = vsr[1];
}
+#else
+ env->fpr[i] = vsr[1];
+ if (vsx) {
+ env->vsr[i] = vsr[0];
+ }
+#endif
}
}
}
next prev parent reply other threads:[~2016-01-15 15:00 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 ` Greg Kurz [this message]
2016-01-18 2:16 ` [Qemu-devel] [PATCH 1/7] target-ppc: kvm: fix floating point registers sync on little-endian hosts 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
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 10:18 ` [Qemu-devel] [PATCH 1/7] target-ppc: kvm: fix floating point registers sync on little-endian hosts Greg Kurz
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