86 lines
2.4 KiB
Diff
86 lines
2.4 KiB
Diff
From: Greg Kurz <gkurz@linux.vnet.ibm.com>
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Date: Fri, 15 Jan 2016 16:00:12 +0100
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Subject: [PATCH] target-ppc: kvm: fix floating point registers sync on
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little-endian hosts
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On VSX capable CPUs, the 32 FP registers are mapped to the high-bits
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of the 32 first VSX registers. So if you have:
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VSR31 = (uint128) 0x0102030405060708090a0b0c0d0e0f00
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then
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FPR31 = (uint64) 0x0102030405060708
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The kernel stores the VSX registers in the fp_state struct following the
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host endian element ordering.
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On big-endian:
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fp_state.fpr[31][0] = 0x0102030405060708
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fp_state.fpr[31][1] = 0x090a0b0c0d0e0f00
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On little-endian:
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fp_state.fpr[31][0] = 0x090a0b0c0d0e0f00
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fp_state.fpr[31][1] = 0x0102030405060708
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The KVM_GET_ONE_REG and KVM_SET_ONE_REG ioctls preserve this ordering, but
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QEMU considers it as big-endian and always copies element [0] to the
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fpr[] array and element [1] to the vsr[] array. This does not work with
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little-endian hosts, and you will get:
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(qemu) p $f31
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0x90a0b0c0d0e0f00
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instead of:
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(qemu) p $f31
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0x102030405060708
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This patch fixes the element ordering for little-endian hosts.
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Signed-off-by: Greg Kurz <gkurz@linux.vnet.ibm.com>
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Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
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(cherry picked from commit 3a4b791b4c13e02537a5cc572fa3de70bc5f68da)
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---
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target-ppc/kvm.c | 12 ++++++++++++
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1 file changed, 12 insertions(+)
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diff --git a/target-ppc/kvm.c b/target-ppc/kvm.c
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index 84ae447..7f789d6 100644
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--- a/target-ppc/kvm.c
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+++ b/target-ppc/kvm.c
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@@ -640,8 +640,13 @@ static int kvm_put_fp(CPUState *cs)
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for (i = 0; i < 32; i++) {
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uint64_t vsr[2];
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+#ifdef HOST_WORDS_BIGENDIAN
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vsr[0] = float64_val(env->fpr[i]);
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vsr[1] = env->vsr[i];
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+#else
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+ vsr[0] = env->vsr[i];
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+ vsr[1] = float64_val(env->fpr[i]);
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+#endif
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reg.addr = (uintptr_t) &vsr;
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reg.id = vsx ? KVM_REG_PPC_VSR(i) : KVM_REG_PPC_FPR(i);
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@@ -711,10 +716,17 @@ static int kvm_get_fp(CPUState *cs)
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vsx ? "VSR" : "FPR", i, strerror(errno));
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return ret;
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} else {
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+#ifdef HOST_WORDS_BIGENDIAN
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env->fpr[i] = vsr[0];
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if (vsx) {
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env->vsr[i] = vsr[1];
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}
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+#else
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+ env->fpr[i] = vsr[1];
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+ if (vsx) {
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+ env->vsr[i] = vsr[0];
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+ }
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+#endif
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}
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}
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}
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