48 lines
1.8 KiB
Diff
48 lines
1.8 KiB
Diff
From cdb34f5003b9001d12d1841e8a4eeab9471ab928 Mon Sep 17 00:00:00 2001
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From: Gerd Hoffmann <kraxel@redhat.com>
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Date: Thu, 1 Jun 2023 09:57:31 +0200
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Subject: [PATCH 22/27] OvmfPkg/PlatformInitLib: limit phys-bits to 46.
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Older linux kernels have problems with phys-bits larger than 46,
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ubuntu 18.04 (kernel 4.15) has been reported to be affected.
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Reduce phys-bits limit from 47 to 46.
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Reported-by: Fiona Ebner <f.ebner@proxmox.com>
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Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
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(cherry picked from commit c1e853769046b322690ad336fdb98966757e7414)
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---
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OvmfPkg/Library/PlatformInitLib/MemDetect.c | 9 ++++++---
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1 file changed, 6 insertions(+), 3 deletions(-)
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diff --git a/OvmfPkg/Library/PlatformInitLib/MemDetect.c b/OvmfPkg/Library/PlatformInitLib/MemDetect.c
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index 1102b00ecbf0..662e7e85bbc5 100644
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--- a/OvmfPkg/Library/PlatformInitLib/MemDetect.c
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+++ b/OvmfPkg/Library/PlatformInitLib/MemDetect.c
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@@ -646,16 +646,19 @@ PlatformAddressWidthFromCpuid (
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));
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if (Valid) {
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- if (PhysBits > 47) {
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+ if (PhysBits > 46) {
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/*
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* Avoid 5-level paging altogether for now, which limits
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* PhysBits to 48. Also avoid using address bit 48, due to sign
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* extension we can't identity-map these addresses (and lots of
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* places in edk2 assume we have everything identity-mapped).
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* So the actual limit is 47.
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+ *
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+ * Also some older linux kernels apparently have problems handling
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+ * phys-bits > 46 correctly, so use that as limit.
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*/
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- DEBUG ((DEBUG_INFO, "%a: limit PhysBits to 47 (avoid 5-level paging)\n", __func__));
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- PhysBits = 47;
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+ DEBUG ((DEBUG_INFO, "%a: limit PhysBits to 46 (avoid 5-level paging)\n", __func__));
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+ PhysBits = 46;
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}
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if (!Page1GSupport && (PhysBits > 40)) {
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--
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2.40.1
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