[RFC PATCH 04/12] x86/xen: Introduce new function to map HYPERVISOR_shared_info on Resume

Anchal Agarwal
2018-06-12T20:56:11Z

Introduce a small function which re-uses shared page's PA allocated
during guest initialization time in reserve_shared_info() and not
allocate new page during resume flow.
It also does the mapping of shared_info_page by calling
xen_hvm_init_shared_info() to use the function.

Signed-off-by: Anchal Agarwal <anchalag@amazon.com>
Reviewed-by: Sebastian Biemueller <sbiemue@amazon.com>
Reviewed-by: Munehisa Kamata <kamatam@amazon.com>
Reviewed-by: Eduardo Valentin <eduval@amazon.com>
CR: https://cr.amazon.com/r/8273203/
---
arch/x86/xen/enlighten_hvm.c | 7 +++++++
arch/x86/xen/xen-ops.h | 1 +
2 files changed, 8 insertions(+)

diff --git a/arch/x86/xen/enlighten_hvm.c b/arch/x86/xen/enlighten_hvm.c
index 754d5391d9fa..2c4bcf92a90a 100644
--- a/arch/x86/xen/enlighten_hvm.c
+++ b/arch/x86/xen/enlighten_hvm.c
@@ -24,6 +24,13 @@

static unsigned long shared_info_pfn;

+void xen_hvm_map_shared_info(void)
+{
+ xen_hvm_init_shared_info();
+ if (shared_info_pfn)
+ HYPERVISOR_shared_info = __va(PFN_PHYS(shared_info_pfn));
+}
+
void xen_hvm_init_shared_info(void)
{
struct xen_add_to_physmap xatp;
diff --git a/arch/x86/xen/xen-ops.h b/arch/x86/xen/xen-ops.h
index f377e1820c6c..94c8a009ab35 100644
--- a/arch/x86/xen/xen-ops.h
+++ b/arch/x86/xen/xen-ops.h
@@ -58,6 +58,7 @@ void xen_enable_syscall(void);
void xen_vcpu_restore(void);

void xen_callback_vector(void);
+void xen_hvm_map_shared_info(void);
void xen_hvm_init_shared_info(void);
void xen_unplug_emulated_devices(void);

--
2.14.3

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