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From: Kairui Song <kasong@redhat.com>
To: linux-kernel@vger.kernel.org
Cc: Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
	Ard Biesheuvel <ardb@kernel.org>,
	"K. Y. Srinivasan" <kys@microsoft.com>,
	Haiyang Zhang <haiyangz@microsoft.com>,
	Wei Liu <wei.liu@kernel.org>, Dexuan Cui <decui@microsoft.com>,
	Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>,
	Dave Young <dyoung@redhat.com>,
	x86@kernel.org, linux-hyperv@vger.kernel.org,
	kexec@lists.infradead.org, Kairui Song <kasong@redhat.com>
Subject: [PATCH 2/2] hyperv_fb: Update screen_info after removing old framebuffer
Date: Wed, 14 Oct 2020 17:24:29 +0800	[thread overview]
Message-ID: <20201014092429.1415040-3-kasong@redhat.com> (raw)
In-Reply-To: <20201014092429.1415040-1-kasong@redhat.com>

On gen2 HyperV VM, hyperv_fb will remove the old framebuffer, the
new allocated framebuffer address could be at a differnt location,
and it's no longer VGA framebuffer. Update screen_info
so that after kexec, kernel won't try to reuse the old invalid
framebuffer address as VGA.

Signed-off-by: Kairui Song <kasong@redhat.com>
---
 drivers/video/fbdev/hyperv_fb.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/drivers/video/fbdev/hyperv_fb.c b/drivers/video/fbdev/hyperv_fb.c
index 02411d89cb46..e36fb1a0ecdb 100644
--- a/drivers/video/fbdev/hyperv_fb.c
+++ b/drivers/video/fbdev/hyperv_fb.c
@@ -1114,8 +1114,15 @@ static int hvfb_getmem(struct hv_device *hdev, struct fb_info *info)
 getmem_done:
 	remove_conflicting_framebuffers(info->apertures,
 					KBUILD_MODNAME, false);
-	if (!gen2vm)
+
+	if (gen2vm) {
+		/* framebuffer is reallocated, clear screen_info to avoid misuse from kexec */
+		screen_info.lfb_size = 0;
+		screen_info.lfb_base = 0;
+		screen_info.orig_video_isVGA = 0;
+	} else {
 		pci_dev_put(pdev);
+	}
 	kfree(info->apertures);
 
 	return 0;
-- 
2.28.0


WARNING: multiple messages have this Message-ID (diff)
From: Kairui Song <kasong@redhat.com>
To: linux-kernel@vger.kernel.org
Cc: Wei Liu <wei.liu@kernel.org>, Kairui Song <kasong@redhat.com>,
	Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>,
	kexec@lists.infradead.org, Haiyang Zhang <haiyangz@microsoft.com>,
	x86@kernel.org, Dexuan Cui <decui@microsoft.com>,
	linux-hyperv@vger.kernel.org, Ingo Molnar <mingo@redhat.com>,
	Borislav Petkov <bp@alien8.de>,
	Thomas Gleixner <tglx@linutronix.de>,
	"K. Y. Srinivasan" <kys@microsoft.com>,
	Dave Young <dyoung@redhat.com>, Ard Biesheuvel <ardb@kernel.org>
Subject: [PATCH 2/2] hyperv_fb: Update screen_info after removing old framebuffer
Date: Wed, 14 Oct 2020 17:24:29 +0800	[thread overview]
Message-ID: <20201014092429.1415040-3-kasong@redhat.com> (raw)
In-Reply-To: <20201014092429.1415040-1-kasong@redhat.com>

On gen2 HyperV VM, hyperv_fb will remove the old framebuffer, the
new allocated framebuffer address could be at a differnt location,
and it's no longer VGA framebuffer. Update screen_info
so that after kexec, kernel won't try to reuse the old invalid
framebuffer address as VGA.

Signed-off-by: Kairui Song <kasong@redhat.com>
---
 drivers/video/fbdev/hyperv_fb.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/drivers/video/fbdev/hyperv_fb.c b/drivers/video/fbdev/hyperv_fb.c
index 02411d89cb46..e36fb1a0ecdb 100644
--- a/drivers/video/fbdev/hyperv_fb.c
+++ b/drivers/video/fbdev/hyperv_fb.c
@@ -1114,8 +1114,15 @@ static int hvfb_getmem(struct hv_device *hdev, struct fb_info *info)
 getmem_done:
 	remove_conflicting_framebuffers(info->apertures,
 					KBUILD_MODNAME, false);
-	if (!gen2vm)
+
+	if (gen2vm) {
+		/* framebuffer is reallocated, clear screen_info to avoid misuse from kexec */
+		screen_info.lfb_size = 0;
+		screen_info.lfb_base = 0;
+		screen_info.orig_video_isVGA = 0;
+	} else {
 		pci_dev_put(pdev);
+	}
 	kfree(info->apertures);
 
 	return 0;
-- 
2.28.0


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kexec@lists.infradead.org
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  parent reply	other threads:[~2020-10-14  9:26 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-10-14  9:24 [PATCH 0/2] x86/hyperv: fix kexec/kdump hang on some VMs Kairui Song
2020-10-14  9:24 ` Kairui Song
2020-10-14  9:24 ` [PATCH 1/2] x86/kexec: Use up-to-dated screen_info copy to fill boot params Kairui Song
2020-10-14  9:24   ` Kairui Song
2020-10-14 15:43   ` [tip: x86/urgent] " tip-bot2 for Kairui Song
2020-10-27 20:07     ` Thomas Gleixner
2020-11-17  3:39   ` [PATCH 1/2] " Dexuan Cui
2020-11-17  3:39     ` Dexuan Cui
2020-11-25 23:39     ` Dexuan Cui
2020-11-25 23:39       ` Dexuan Cui
2020-10-14  9:24 ` Kairui Song [this message]
2020-10-14  9:24   ` [PATCH 2/2] hyperv_fb: Update screen_info after removing old framebuffer Kairui Song
2020-10-14 15:43   ` [tip: x86/urgent] " tip-bot2 for Kairui Song

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