[PATCH v2 3/6] arch:x86:hv: Add mechanism for Hyper-V paravirt drivers to hook msi message creation

From: jakeo
Date: Mon Jun 15 2015 - 13:09:43 EST


From: Jake Oshins <jakeo@xxxxxxxxxxxxx>

This patch, when the kernel is built with CONFIG_HYPERV, exposes functions
that would allow a paravirtual PCI front-end driver to hook MSI (message-
signaled interrupt) message creation.

Signed-off-by: Jake Oshins <jakeo@xxxxxxxxxxxxx>
---
arch/x86/include/asm/mshyperv.h | 2 ++
arch/x86/kernel/cpu/mshyperv.c | 30 ++++++++++++++++++++++++++++++
2 files changed, 32 insertions(+)

diff --git a/arch/x86/include/asm/mshyperv.h b/arch/x86/include/asm/mshyperv.h
index c163215..bf7789e 100644
--- a/arch/x86/include/asm/mshyperv.h
+++ b/arch/x86/include/asm/mshyperv.h
@@ -19,5 +19,7 @@ void hyperv_callback_vector(void);
void hyperv_vector_handler(struct pt_regs *regs);
void hv_setup_vmbus_irq(void (*handler)(void));
void hv_remove_vmbus_irq(void);
+void hyperv_install_interrupt_translation(struct x86_msi_ops *new_ops);
+void hyperv_uninstall_interrupt_translation(void);

#endif
diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c
index 939155f..816e329 100644
--- a/arch/x86/kernel/cpu/mshyperv.c
+++ b/arch/x86/kernel/cpu/mshyperv.c
@@ -69,6 +69,36 @@ void hv_remove_vmbus_irq(void)
}
EXPORT_SYMBOL_GPL(hv_setup_vmbus_irq);
EXPORT_SYMBOL_GPL(hv_remove_vmbus_irq);
+
+struct x86_msi_ops old_msi_ops;
+
+void hyperv_install_interrupt_translation(struct x86_msi_ops *new_ops)
+{
+ old_msi_ops.setup_msi_irqs = xchg(&(x86_msi.setup_msi_irqs),
+ new_ops->setup_msi_irqs);
+ old_msi_ops.compose_msi_msg = xchg(&(x86_msi.compose_msi_msg),
+ new_ops->compose_msi_msg);
+ old_msi_ops.teardown_msi_irqs = xchg(&(x86_msi.teardown_msi_irqs),
+ new_ops->teardown_msi_irqs);
+ old_msi_ops.restore_msi_irqs = xchg(&(x86_msi.restore_msi_irqs),
+ new_ops->restore_msi_irqs);
+
+ new_ops->setup_msi_irqs = old_msi_ops.setup_msi_irqs;
+ new_ops->compose_msi_msg = old_msi_ops.compose_msi_msg;
+ new_ops->teardown_msi_irqs = old_msi_ops.teardown_msi_irqs;
+ new_ops->restore_msi_irqs = old_msi_ops.restore_msi_irqs;
+}
+EXPORT_SYMBOL_GPL(hyperv_install_interrupt_translation);
+
+void hyperv_uninstall_interrupt_translation(void)
+{
+ xchg(&(x86_msi.setup_msi_irqs), old_msi_ops.setup_msi_irqs);
+ xchg(&(x86_msi.compose_msi_msg), old_msi_ops.compose_msi_msg);
+ xchg(&(x86_msi.teardown_msi_irqs), old_msi_ops.teardown_msi_irqs);
+ xchg(&(x86_msi.restore_msi_irqs), old_msi_ops.restore_msi_irqs);
+}
+EXPORT_SYMBOL_GPL(hyperv_uninstall_interrupt_translation);
+
#endif

static uint32_t __init ms_hyperv_platform(void)
--
1.9.1

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