From: Juergen Gross <jgross@suse.com>
To: linux-kernel@vger.kernel.org, x86@kernel.org
Cc: Juergen Gross <jgross@suse.com>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
Dave Hansen <dave.hansen@linux.intel.com>,
"H. Peter Anvin" <hpa@zytor.com>,
Linus Torvalds <torvalds@linux-foundation.org>
Subject: [PATCH v4 11/12] x86/mtrr: don't let mtrr_type_lookup() return MTRR_TYPE_INVALID
Date: Mon, 6 Mar 2023 17:34:24 +0100 [thread overview]
Message-ID: <20230306163425.8324-12-jgross@suse.com> (raw)
In-Reply-To: <20230306163425.8324-1-jgross@suse.com>
mtrr_type_lookup() should always return a valid memory type. In case
there is no information available, it should return the default UC.
This will remove the last case where mtrr_type_lookup() can return
MTRR_TYPE_INVALID, so adjust the comment in include/uapi/asm/mtrr.h.
Note that removing the MTRR_TYPE_INVALID #define from that header
could break user code, so it has to stay.
At the same time the mtrr_type_lookup() stub for the !CONFIG_MTRR
case should set uniform to 1, as if the memory range would be
covered by no MTRR at all.
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Juergen Gross <jgross@suse.com>
---
V2:
- always set uniform
- set uniform to 1 in case of disabled MTRRs (Linus Torvalds)
V3:
- adjust include/uapi/asm/mtrr.h comment
---
arch/x86/include/asm/mtrr.h | 7 +++++--
arch/x86/include/uapi/asm/mtrr.h | 6 +++---
arch/x86/kernel/cpu/mtrr/generic.c | 4 ++--
3 files changed, 10 insertions(+), 7 deletions(-)
diff --git a/arch/x86/include/asm/mtrr.h b/arch/x86/include/asm/mtrr.h
index f1cb81330a64..0d7ea8a54d81 100644
--- a/arch/x86/include/asm/mtrr.h
+++ b/arch/x86/include/asm/mtrr.h
@@ -59,9 +59,12 @@ static inline void mtrr_overwrite_state(struct mtrr_var_range *var,
static inline u8 mtrr_type_lookup(u64 addr, u64 end, u8 *uniform)
{
/*
- * Return no-MTRRs:
+ * Return the default MTRR type, without any known other types in
+ * that range.
*/
- return MTRR_TYPE_INVALID;
+ *uniform = 1;
+
+ return MTRR_TYPE_UNCACHABLE;
}
#define mtrr_save_fixed_ranges(arg) do {} while (0)
#define mtrr_save_state() do {} while (0)
diff --git a/arch/x86/include/uapi/asm/mtrr.h b/arch/x86/include/uapi/asm/mtrr.h
index 376563f2bac1..4aa05c2ffa78 100644
--- a/arch/x86/include/uapi/asm/mtrr.h
+++ b/arch/x86/include/uapi/asm/mtrr.h
@@ -115,9 +115,9 @@ struct mtrr_state_type {
#define MTRR_NUM_TYPES 7
/*
- * Invalid MTRR memory type. mtrr_type_lookup() returns this value when
- * MTRRs are disabled. Note, this value is allocated from the reserved
- * values (0x7-0xff) of the MTRR memory types.
+ * Invalid MTRR memory type. No longer used outside of MTRR code.
+ * Note, this value is allocated from the reserved values (0x7-0xff) of
+ * the MTRR memory types.
*/
#define MTRR_TYPE_INVALID 0xff
diff --git a/arch/x86/kernel/cpu/mtrr/generic.c b/arch/x86/kernel/cpu/mtrr/generic.c
index de6d74d6e3a0..3d48e9d06bfb 100644
--- a/arch/x86/kernel/cpu/mtrr/generic.c
+++ b/arch/x86/kernel/cpu/mtrr/generic.c
@@ -417,13 +417,13 @@ u8 mtrr_type_lookup(u64 start, u64 end, u8 *uniform)
if (!mtrr_state_set) {
*uniform = 0; /* Uniformity is unknown. */
- return MTRR_TYPE_INVALID;
+ return MTRR_TYPE_UNCACHABLE;
}
*uniform = 1;
if (!(mtrr_state.enabled & MTRR_STATE_MTRR_ENABLED))
- return MTRR_TYPE_INVALID;
+ return MTRR_TYPE_UNCACHABLE;
for (i = 0; i < cache_map_n && start < end; i++) {
if (start >= cache_map[i].end)
--
2.35.3
next prev parent reply other threads:[~2023-03-06 16:37 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-03-06 16:34 [PATCH v4 00/12] x86/mtrr: fix handling with PAT but without MTRR Juergen Gross
2023-03-06 16:34 ` [PATCH v4 01/12] x86/mtrr: split off physical address size calculation Juergen Gross
2023-03-06 16:34 ` [PATCH v4 02/12] x86/mtrr: optimize mtrr_calc_physbits() Juergen Gross
2023-03-20 12:50 ` Borislav Petkov
2023-03-06 16:34 ` [PATCH v4 03/12] x86/mtrr: support setting MTRR state for software defined MTRRs Juergen Gross
2023-03-20 12:59 ` Huang, Kai
2023-03-20 13:47 ` Juergen Gross
2023-03-20 21:34 ` Huang, Kai
2023-03-20 22:42 ` Borislav Petkov
2023-03-21 6:01 ` Juergen Gross
2023-03-20 19:05 ` Borislav Petkov
2023-03-21 6:00 ` Juergen Gross
2023-03-21 10:30 ` Borislav Petkov
2023-03-21 15:49 ` Juergen Gross
2023-03-06 16:34 ` [PATCH v4 04/12] x86/hyperv: set MTRR state when running as SEV-SNP Hyper-V guest Juergen Gross
2023-03-06 16:34 ` [PATCH v4 05/12] x86/xen: set MTRR state when running as Xen PV initial domain Juergen Gross
2023-03-07 21:47 ` Boris Ostrovsky
2023-03-23 12:43 ` Borislav Petkov
2023-03-06 16:34 ` [PATCH v4 06/12] x86/mtrr: replace vendor tests in MTRR code Juergen Gross
2023-03-24 16:56 ` Borislav Petkov
2023-03-27 5:43 ` Juergen Gross
2023-03-27 7:14 ` Borislav Petkov
2023-03-06 16:34 ` [PATCH v4 07/12] x86/mtrr: allocate mtrr_value array dynamically Juergen Gross
2023-03-20 12:25 ` Huang, Kai
2023-03-20 13:49 ` Juergen Gross
2023-03-20 15:31 ` Dave Hansen
2023-03-20 15:49 ` Juergen Gross
2023-03-26 22:05 ` Borislav Petkov
2023-03-27 5:44 ` Juergen Gross
2023-03-06 16:34 ` [PATCH v4 08/12] x86/mtrr: add get_effective_type() service function Juergen Gross
2023-03-06 16:34 ` [PATCH v4 09/12] x86/mtrr: construct a memory map with cache modes Juergen Gross
2023-03-29 12:51 ` Borislav Petkov
2023-03-29 13:39 ` Juergen Gross
2023-03-31 12:55 ` Borislav Petkov
2023-03-31 13:23 ` Juergen Gross
2023-04-01 14:24 ` Borislav Petkov
2023-04-03 6:57 ` Juergen Gross
2023-03-31 12:57 ` Borislav Petkov
2023-03-31 13:35 ` Juergen Gross
2023-04-01 14:26 ` Borislav Petkov
2023-04-03 7:02 ` Juergen Gross
2023-03-06 16:34 ` [PATCH v4 10/12] x86/mtrr: use new cache_map in mtrr_type_lookup() Juergen Gross
2023-03-06 16:34 ` Juergen Gross [this message]
2023-03-06 16:34 ` [PATCH v4 12/12] x86/mm: only check uniform after calling mtrr_type_lookup() Juergen Gross
2023-03-07 21:09 ` [PATCH v4 00/12] x86/mtrr: fix handling with PAT but without MTRR Michael Kelley (LINUX)
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