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From 5f462874a5ee6471faa55f05d3a09369a5dcff2d Mon Sep 17 00:00:00 2001
From: Juergen Gross <jgross@suse.com>
Date: Fri, 7 Dec 2018 13:11:39 +0100
Subject: [PATCH 11/20] xen: Setup hypercall page for PVH
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Add the needed code to setup the hypercall page for calling into the
Xen hypervisor.
Import the XEN_HVM_DEBUGCONS_IOPORT define from Xen unstable into
include/xen/arch-x86/xen.h
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Roger Pau Monné <roger.pau@citrix.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
Tested-by: Hans van Kranenburg <hans@knorrie.org>
(cherry picked from commit da81e42a7ccb545513368ec7488cdf5019c1c2ba)
---
grub-core/kern/i386/xen/pvh.c | 80 +++++++++++++++++++++++++++++++++++
include/xen/arch-x86/xen.h | 7 +++
2 files changed, 87 insertions(+)
diff --git a/grub-core/kern/i386/xen/pvh.c b/grub-core/kern/i386/xen/pvh.c
index 4f629b15e..a2554fb1d 100644
--- a/grub-core/kern/i386/xen/pvh.c
+++ b/grub-core/kern/i386/xen/pvh.c
@@ -20,15 +20,95 @@
#include <grub/misc.h>
#include <grub/memory.h>
#include <grub/mm.h>
+#include <grub/i386/cpuid.h>
+#include <grub/i386/io.h>
#include <grub/xen.h>
#include <xen/hvm/start_info.h>
#include <grub/machine/kernel.h>
grub_uint64_t grub_rsdp_addr;
+static char hypercall_page[GRUB_XEN_PAGE_SIZE]
+ __attribute__ ((aligned (GRUB_XEN_PAGE_SIZE)));
+
+static grub_uint32_t xen_cpuid_base;
+
+static void
+grub_xen_cons_msg (const char *msg)
+{
+ const char *c;
+
+ for (c = msg; *c; c++)
+ grub_outb (*c, XEN_HVM_DEBUGCONS_IOPORT);
+}
+
+static void
+grub_xen_panic (const char *msg)
+{
+ grub_xen_cons_msg (msg);
+ grub_xen_cons_msg ("System halted!\n");
+
+ asm volatile ("cli");
+
+ while (1)
+ {
+ asm volatile ("hlt");
+ }
+}
+
+static void
+grub_xen_cpuid_base (void)
+{
+ grub_uint32_t base, eax, signature[3];
+
+ for (base = 0x40000000; base < 0x40010000; base += 0x100)
+ {
+ grub_cpuid (base, eax, signature[0], signature[1], signature[2]);
+ if (!grub_memcmp ("XenVMMXenVMM", signature, 12) && (eax - base) >= 2)
+ {
+ xen_cpuid_base = base;
+ return;
+ }
+ }
+
+ grub_xen_panic ("Found no Xen signature!\n");
+}
+
+static void
+grub_xen_setup_hypercall_page (void)
+{
+ grub_uint32_t msr, addr, eax, ebx, ecx, edx;
+
+ /* Get base address of Xen-specific MSRs. */
+ grub_cpuid (xen_cpuid_base + 2, eax, ebx, ecx, edx);
+ msr = ebx;
+ addr = (grub_uint32_t) (&hypercall_page);
+
+ /* Specify hypercall page address for Xen. */
+ asm volatile ("wrmsr" : : "c" (msr), "a" (addr), "d" (0) : "memory");
+}
+
+int
+grub_xen_hypercall (grub_uint32_t callno, grub_uint32_t a0,
+ grub_uint32_t a1, grub_uint32_t a2,
+ grub_uint32_t a3, grub_uint32_t a4,
+ grub_uint32_t a5 __attribute__ ((unused)))
+{
+ grub_uint32_t res;
+
+ asm volatile ("call *%[callno]"
+ : "=a" (res), "+b" (a0), "+c" (a1), "+d" (a2),
+ "+S" (a3), "+D" (a4)
+ : [callno] "a" (&hypercall_page[callno * 32])
+ : "memory");
+ return res;
+}
+
void
grub_xen_setup_pvh (void)
{
+ grub_xen_cpuid_base ();
+ grub_xen_setup_hypercall_page ();
}
grub_err_t
diff --git a/include/xen/arch-x86/xen.h b/include/xen/arch-x86/xen.h
index f35804b88..56be26cb6 100644
--- a/include/xen/arch-x86/xen.h
+++ b/include/xen/arch-x86/xen.h
@@ -260,6 +260,13 @@ typedef struct arch_shared_info arch_shared_info_t;
#define XEN_CPUID XEN_EMULATE_PREFIX "cpuid"
#endif
+/*
+ * Debug console IO port, also called "port E9 hack". Each character written
+ * to this IO port will be printed on the hypervisor console, subject to log
+ * level restrictions.
+ */
+#define XEN_HVM_DEBUGCONS_IOPORT 0xe9
+
#endif /* __XEN_PUBLIC_ARCH_X86_XEN_H__ */
/*
--
2.21.0
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