All of lore.kernel.org
 help / color / mirror / Atom feed
* [PATCH v6][RESEND] x86/hyperv: Suspend/resume the hypercall page for hibernation
@ 2020-01-06 22:42 Dexuan Cui
  2020-01-25  1:44 ` Dexuan Cui
  2020-02-01  8:48 ` [tip: x86/urgent] " tip-bot2 for Dexuan Cui
  0 siblings, 2 replies; 7+ messages in thread
From: Dexuan Cui @ 2020-01-06 22:42 UTC (permalink / raw)
  To: arnd, bp, daniel.lezcano, haiyangz, hpa, kys, linux-hyperv,
	linux-kernel, mingo, sashal, sthemmin, tglx, x86, mikelley,
	Alexander.Levin, vkuznets
  Cc: linux-arch, Dexuan Cui

This is needed for hibernation, e.g. when we resume the old kernel, we need
to disable the "current" kernel's hypercall page and then resume the old
kernel's.

Signed-off-by: Dexuan Cui <decui@microsoft.com>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
---

This is a RESEND of https://lkml.org/lkml/2019/11/20/68 .

Please review.

If it looks good, can you please pick it up through the tip.git tree?


 arch/x86/hyperv/hv_init.c | 48 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 48 insertions(+)

diff --git a/arch/x86/hyperv/hv_init.c b/arch/x86/hyperv/hv_init.c
index caaf4dce99bf..24a62d33067c 100644
--- a/arch/x86/hyperv/hv_init.c
+++ b/arch/x86/hyperv/hv_init.c
@@ -21,11 +21,15 @@
 #include <linux/hyperv.h>
 #include <linux/slab.h>
 #include <linux/cpuhotplug.h>
+#include <linux/syscore_ops.h>
 #include <clocksource/hyperv_timer.h>
 
 void *hv_hypercall_pg;
 EXPORT_SYMBOL_GPL(hv_hypercall_pg);
 
+/* Save the hypercall page temporarily for hibernation */
+static void *hv_hypercall_pg_saved;
+
 u32 *hv_vp_index;
 EXPORT_SYMBOL_GPL(hv_vp_index);
 
@@ -246,6 +250,46 @@ static int __init hv_pci_init(void)
 	return 1;
 }
 
+static int hv_suspend(void)
+{
+	union hv_x64_msr_hypercall_contents hypercall_msr;
+
+	/*
+	 * Reset hypercall page reference before reset the page,
+	 * let hypercall operations fail safely rather than
+	 * panic the kernel for using invalid hypercall page
+	 */
+	hv_hypercall_pg_saved = hv_hypercall_pg;
+	hv_hypercall_pg = NULL;
+
+	/* Reset the hypercall page */
+	rdmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
+	hypercall_msr.enable = 0;
+	wrmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
+
+	return 0;
+}
+
+static void hv_resume(void)
+{
+	union hv_x64_msr_hypercall_contents hypercall_msr;
+
+	/* Re-enable the hypercall page */
+	rdmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
+	hypercall_msr.enable = 1;
+	hypercall_msr.guest_physical_address =
+		vmalloc_to_pfn(hv_hypercall_pg_saved);
+	wrmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
+
+	hv_hypercall_pg = hv_hypercall_pg_saved;
+	hv_hypercall_pg_saved = NULL;
+}
+
+static struct syscore_ops hv_syscore_ops = {
+	.suspend = hv_suspend,
+	.resume = hv_resume,
+};
+
 /*
  * This function is to be invoked early in the boot sequence after the
  * hypervisor has been detected.
@@ -330,6 +374,8 @@ void __init hyperv_init(void)
 
 	x86_init.pci.arch_init = hv_pci_init;
 
+	register_syscore_ops(&hv_syscore_ops);
+
 	return;
 
 remove_cpuhp_state:
@@ -349,6 +395,8 @@ void hyperv_cleanup(void)
 {
 	union hv_x64_msr_hypercall_contents hypercall_msr;
 
+	unregister_syscore_ops(&hv_syscore_ops);
+
 	/* Reset our OS id */
 	wrmsrl(HV_X64_MSR_GUEST_OS_ID, 0);
 
-- 
2.19.1


^ permalink raw reply related	[flat|nested] 7+ messages in thread
end of thread, other threads:[~2020-02-01  8:48 UTC | newest]

Thread overview: 7+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-01-06 22:42 [PATCH v6][RESEND] x86/hyperv: Suspend/resume the hypercall page for hibernation Dexuan Cui
2020-01-25  1:44 ` Dexuan Cui
2020-01-30  0:05   ` Sasha Levin
2020-01-30  1:02     ` Dexuan Cui
2020-01-30  7:37     ` Thomas Gleixner
2020-01-30  7:37       ` Thomas Gleixner
2020-02-01  8:48 ` [tip: x86/urgent] " tip-bot2 for Dexuan Cui

This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.