From: Isaku Yamahata <yamahata@valinux.co.jp>
Date: Fri, 12 Dec 2008 01:35:58 +0000 (+0900)
Subject: IA64: make the fpswa emulation keep the previous behaviour.
X-Git-Tag: archive/raspbian/4.8.0-1+rpi1~1^2~14031
X-Git-Url: https://dgit.raspbian.org/?a=commitdiff_plain;h=8344be4d2fce09d2fbf3e47cfcf0b9efa07f9cc6;p=xen.git

IA64: make the fpswa emulation keep the previous behaviour.

When fpswa library return statue > 0, keep the previous behavior.
This case should be addressed somehow later, but it seems somewhat
difficult to resolve, so keep the previous behavor for now.
It is assumed that a guest kernel calls fpswa library
without preemption. This assumption breaks if a guest kernel is
preemptive.

Signed-off-by: Isaku Yamahata <yamahata@valinux.co.jp>
---

diff --git a/xen/arch/ia64/xen/faults.c b/xen/arch/ia64/xen/faults.c
index d1327e8681..7aec52d3b0 100644
--- a/xen/arch/ia64/xen/faults.c
+++ b/xen/arch/ia64/xen/faults.c
@@ -337,6 +337,7 @@ handle_fpu_swa(int fp_fault, struct pt_regs *regs, unsigned long isr)
 			rc = IA64_RETRY;
 	}
 	if (rc == IA64_RETRY) {
+		PSCBX(current, fpswa_ret) = (fpswa_ret_t){IA64_RETRY, 0, 0, 0};
 		gdprintk(XENLOG_DEBUG,
 			 "%s(%s): floating-point bundle at 0x%lx not mapped\n",
 			 __FUNCTION__, fp_fault ? "fault" : "trap", fault_ip);
@@ -347,6 +348,7 @@ handle_fpu_swa(int fp_fault, struct pt_regs *regs, unsigned long isr)
 	                 &isr, &regs->pr, &regs->cr_ifs, regs);
 
 	if (ret.status) {
+		PSCBX(current, fpswa_ret) = ret;
 		printk("%s(%s): fp_emulate() returned %ld\n",
 		       __FUNCTION__, fp_fault ? "fault" : "trap", ret.status);
 	}
diff --git a/xen/arch/ia64/xen/hypercall.c b/xen/arch/ia64/xen/hypercall.c
index 0ae317e96e..f727729746 100644
--- a/xen/arch/ia64/xen/hypercall.c
+++ b/xen/arch/ia64/xen/hypercall.c
@@ -165,6 +165,13 @@ fw_hypercall_fpswa (struct vcpu *v, struct pt_regs *regs)
 	struct page_info *hv_page = NULL;
 	XEN_EFI_RR_DECLARE(rr6, rr7);
 
+	if (unlikely(PSCBX(v, fpswa_ret).status != 0 && 
+		     PSCBX(v, fpswa_ret).status != IA64_RETRY)) {
+		ret = PSCBX(v, fpswa_ret);
+		PSCBX(v, fpswa_ret) = (fpswa_ret_t){0, 0, 0, 0};
+		return ret;
+	}
+
 	if (!fpswa_interface)
 		goto error;
 
diff --git a/xen/include/asm-ia64/domain.h b/xen/include/asm-ia64/domain.h
index 2c9f21f089..f04ed5b790 100644
--- a/xen/include/asm-ia64/domain.h
+++ b/xen/include/asm-ia64/domain.h
@@ -288,6 +288,7 @@ struct arch_vcpu {
     char irq_new_condition;    // vpsr.i/vtpr change, check for pending VHPI
     char hypercall_continuation;
 
+    fpswa_ret_t fpswa_ret;     /* save return values of FPSWA emulation */
     struct timer hlt_timer;
     struct arch_vmx_struct arch_vmx; /* Virtual Machine Extensions */