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Subject[PATCH 28/43] KVM: ia64: Drop in SN2 replacement of fast path ITC emulation fault handler
Date
From: Jes Sorensen <jes@sgi.com>

Copy in SN2 RTC based ITC emulation for fast exit. The two versions
have the same size, so a dropin is simpler than patching the branch
instruction to hit the SN2 version.

Signed-off-by: Jes Sorensen <jes@sgi.com>
Acked-by: Xiantao Zhang <xiantao.zhang@intel.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
---
arch/ia64/include/asm/kvm_host.h | 2 ++
arch/ia64/kvm/kvm-ia64.c | 32 +++++++++++++++++++++++++++++++-
arch/ia64/kvm/optvfault.S | 30 ++++++++++++++++++++++++++++++
arch/ia64/kvm/vmm.c | 12 ++++++++----
4 files changed, 71 insertions(+), 5 deletions(-)

diff --git a/arch/ia64/include/asm/kvm_host.h b/arch/ia64/include/asm/kvm_host.h
index 1243995..589536f 100644
--- a/arch/ia64/include/asm/kvm_host.h
+++ b/arch/ia64/include/asm/kvm_host.h
@@ -580,6 +580,8 @@ struct kvm_vmm_info{
kvm_vmm_entry *vmm_entry;
kvm_tramp_entry *tramp_entry;
unsigned long vmm_ivt;
+ unsigned long patch_mov_ar;
+ unsigned long patch_mov_ar_sn2;
};

int kvm_highest_pending_irq(struct kvm_vcpu *vcpu);
diff --git a/arch/ia64/kvm/kvm-ia64.c b/arch/ia64/kvm/kvm-ia64.c
index ebbd995..4623a90 100644
--- a/arch/ia64/kvm/kvm-ia64.c
+++ b/arch/ia64/kvm/kvm-ia64.c
@@ -1671,8 +1671,37 @@ out:
return 0;
}

+
+/*
+ * On SN2, the ITC isn't stable, so copy in fast path code to use the
+ * SN2 RTC, replacing the ITC based default verion.
+ */
+static void kvm_patch_vmm(struct kvm_vmm_info *vmm_info,
+ struct module *module)
+{
+ unsigned long new_ar, new_ar_sn2;
+ unsigned long module_base;
+
+ if (!ia64_platform_is("sn2"))
+ return;
+
+ module_base = (unsigned long)module->module_core;
+
+ new_ar = kvm_vmm_base + vmm_info->patch_mov_ar - module_base;
+ new_ar_sn2 = kvm_vmm_base + vmm_info->patch_mov_ar_sn2 - module_base;
+
+ printk(KERN_INFO "kvm: Patching ITC emulation to use SGI SN2 RTC "
+ "as source\n");
+
+ /*
+ * Copy the SN2 version of mov_ar into place. They are both
+ * the same size, so 6 bundles is sufficient (6 * 0x10).
+ */
+ memcpy((void *)new_ar, (void *)new_ar_sn2, 0x60);
+}
+
static int kvm_relocate_vmm(struct kvm_vmm_info *vmm_info,
- struct module *module)
+ struct module *module)
{
unsigned long module_base;
unsigned long vmm_size;
@@ -1694,6 +1723,7 @@ static int kvm_relocate_vmm(struct kvm_vmm_info *vmm_info,
return -EFAULT;

memcpy((void *)kvm_vmm_base, (void *)module_base, vmm_size);
+ kvm_patch_vmm(vmm_info, module);
kvm_flush_icache(kvm_vmm_base, vmm_size);

/*Recalculate kvm_vmm_info based on new VMM*/
diff --git a/arch/ia64/kvm/optvfault.S b/arch/ia64/kvm/optvfault.S
index 32254ce..f793be3 100644
--- a/arch/ia64/kvm/optvfault.S
+++ b/arch/ia64/kvm/optvfault.S
@@ -11,6 +11,7 @@

#include <asm/asmmacro.h>
#include <asm/processor.h>
+#include <asm/kvm_host.h>

#include "vti.h"
#include "asm-offsets.h"
@@ -140,6 +141,35 @@ GLOBAL_ENTRY(kvm_asm_mov_from_ar)
;;
END(kvm_asm_mov_from_ar)

+/*
+ * Special SGI SN2 optimized version of mov_from_ar using the SN2 RTC
+ * clock as it's source for emulating the ITC. This version will be
+ * copied on top of the original version if the host is determined to
+ * be an SN2.
+ */
+GLOBAL_ENTRY(kvm_asm_mov_from_ar_sn2)
+ add r18=VMM_VCPU_ITC_OFS_OFFSET, r21
+ movl r19 = (KVM_VMM_BASE+(1<<KVM_VMM_SHIFT))
+
+ add r16=VMM_VCPU_LAST_ITC_OFFSET,r21
+ extr.u r17=r25,6,7
+ mov r24=b0
+ ;;
+ ld8 r18=[r18]
+ ld8 r19=[r19]
+ addl r20=@gprel(asm_mov_to_reg),gp
+ ;;
+ add r19=r19,r18
+ shladd r17=r17,4,r20
+ ;;
+ adds r30=kvm_resume_to_guest-asm_mov_to_reg,r20
+ st8 [r16] = r19
+ mov b0=r17
+ br.sptk.few b0
+ ;;
+END(kvm_asm_mov_from_ar_sn2)
+
+

// mov r1=rr[r3]
GLOBAL_ENTRY(kvm_asm_mov_from_rr)
diff --git a/arch/ia64/kvm/vmm.c b/arch/ia64/kvm/vmm.c
index 9eee5c0..f4b4c89 100644
--- a/arch/ia64/kvm/vmm.c
+++ b/arch/ia64/kvm/vmm.c
@@ -30,15 +30,19 @@ MODULE_AUTHOR("Intel");
MODULE_LICENSE("GPL");

extern char kvm_ia64_ivt;
+extern char kvm_asm_mov_from_ar;
+extern char kvm_asm_mov_from_ar_sn2;
extern fpswa_interface_t *vmm_fpswa_interface;

long vmm_sanity = 1;

struct kvm_vmm_info vmm_info = {
- .module = THIS_MODULE,
- .vmm_entry = vmm_entry,
- .tramp_entry = vmm_trampoline,
- .vmm_ivt = (unsigned long)&kvm_ia64_ivt,
+ .module = THIS_MODULE,
+ .vmm_entry = vmm_entry,
+ .tramp_entry = vmm_trampoline,
+ .vmm_ivt = (unsigned long)&kvm_ia64_ivt,
+ .patch_mov_ar = (unsigned long)&kvm_asm_mov_from_ar,
+ .patch_mov_ar_sn2 = (unsigned long)&kvm_asm_mov_from_ar_sn2,
};

static int __init kvm_vmm_init(void)
--
1.6.0.6


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