qemu/target
Alexander Graf c363ebaa19 target/i386: Walk NPT in guest real mode
When translating virtual to physical address with a guest CPU that
supports nested paging (NPT), we need to perform every page table walk
access indirectly through the NPT, which we correctly do.

However, we treat real mode (no page table walk) special: In that case,
we currently just skip any walks and translate VA -> PA. With NPT
enabled, we also need to then perform NPT walk to do GVA -> GPA -> HPA
which we fail to do so far.

The net result of that is that TCG VMs with NPT enabled that execute
real mode code (like SeaBIOS) end up with GPA==HPA mappings which means
the guest accesses host code and data. This typically shows as failure
to boot guests.

This patch changes the page walk logic for NPT enabled guests so that we
always perform a GVA -> GPA translation and then skip any logic that
requires an actual PTE.

That way, all remaining logic to walk the NPT stays and we successfully
walk the NPT in real mode.

Cc: qemu-stable@nongnu.org
Fixes: fe441054bb ("target-i386: Add NPT support")
Signed-off-by: Alexander Graf <graf@amazon.com>
Reported-by: Eduard Vlad <evlad@amazon.de>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-ID: <20240921085712.28902-1-graf@amazon.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
(cherry picked from commit b56617bbcb)
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
2024-11-10 11:10:00 +03:00
..
alpha accel/tcg: Remove will_exit argument from cpu_restore_state 2022-11-01 08:31:41 +11:00
arm target/arm: Handle denormals correctly for FMOPA (widening) 2024-08-02 14:01:04 +03:00
avr target/avr: Convert to tcg_ops restore_state_to_opc 2022-10-26 11:11:28 +10:00
cris accel/tcg: Remove will_exit argument from cpu_restore_state 2022-11-01 08:31:41 +11:00
hexagon target/hexagon: Convert to tcg_ops restore_state_to_opc 2022-10-26 11:11:28 +10:00
hppa target/hppa: Clear psw_n for BE on use_nullify_skip path 2024-04-09 20:09:20 +03:00
i386 target/i386: Walk NPT in guest real mode 2024-11-10 11:10:00 +03:00
loongarch target/loongarch: fix a wrong print in cpu dump 2024-06-07 08:10:49 +03:00
m68k target/m68k: Fix semihost lseek offset computation 2023-08-03 08:26:26 +03:00
microblaze accel/tcg: Remove will_exit argument from cpu_restore_state 2022-11-01 08:31:41 +11:00
mips target/mips: Fix TX79 LQ/SQ opcodes 2023-11-19 21:15:23 +03:00
nios2 target/nios2: Fix semihost lseek offset computation 2023-08-03 08:26:26 +03:00
openrisc accel/tcg: Remove will_exit argument from cpu_restore_state 2022-11-01 08:31:41 +11:00
ppc target/ppc: Fix lxvx/stxvx facility check 2024-09-28 07:25:13 +03:00
riscv target/riscv: Fix mcycle/minstret increment behavior 2024-01-08 19:24:44 +03:00
rx target/rx: Use target_ulong for address in LI 2024-07-30 22:28:41 +03:00
s390x target/s390x: Fix LAE setting a wrong access register 2024-01-13 11:28:02 +03:00
sh4 target/sh4: add missing CHECK_NOT_DELAY_SLOT 2024-04-10 20:40:02 +03:00
sparc target/sparc: Convert to tcg_ops restore_state_to_opc 2022-10-26 11:11:28 +10:00
tricore target/tricore: Rename tricore_feature 2023-11-19 21:15:23 +03:00
xtensa target/xtensa: fix OOB TLB entry access 2024-01-27 18:05:30 +03:00
Kconfig hw/loongarch: Add support loongson3 virt machine type. 2022-06-06 18:09:03 +00:00
meson.build target/loongarch: Add target build suport 2022-06-06 18:09:03 +00:00