Rust, i386, accelerator changes for 2025-10-14

[PULL 07/28] target/i386: Fix CR2 handling for non-canonical addresses

Paolo Bonzini posted 28 patches 1 month ago

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Maintainers: Paolo Bonzini <pbonzini@redhat.com>, "Dr. David Alan Gilbert" <dave@treblig.org>, Eduardo Habkost <eduardo@habkost.net>, Marcel Apfelbaum <marcel.apfelbaum@gmail.com>, "Philippe Mathieu-Daudé" <philmd@linaro.org>, Yanan Wang <wangyanan55@huawei.com>, Zhao Liu <zhao1.liu@intel.com>, "Michael S. Tsirkin" <mst@redhat.com>, Eric Blake <eblake@redhat.com>, Markus Armbruster <armbru@redhat.com>, Richard Henderson <richard.henderson@linaro.org>, Manos Pitsidianakis <manos.pitsidianakis@linaro.org>, Peter Maydell <peter.maydell@linaro.org>, Marcelo Tosatti <mtosatti@redhat.com>, Song Gao <gaosong@loongson.cn>, Huacai Chen <chenhuacai@kernel.org>, Aurelien Jarno <aurelien@aurel32.net>, Jiaxun Yang <jiaxun.yang@flygoat.com>, Aleksandar Rikalo <arikalo@gmail.com>, Nicholas Piggin <npiggin@gmail.com>, Harsh Prateek Bora <harshpb@linux.ibm.com>, Chinmay Rath <rathc@linux.ibm.com>, Palmer Dabbelt <palmer@dabbelt.com>, Alistair Francis <alistair.francis@wdc.com>, Weiwei Li <liwei1518@gmail.com>, Daniel Henrique Barboza <dbarboza@ventanamicro.com>, Liu Zhiwei <zhiwei_liu@linux.alibaba.com>, Halil Pasic <pasic@linux.ibm.com>, Christian Borntraeger <borntraeger@linux.ibm.com>, Eric Farman <farman@linux.ibm.com>, Matthew Rosato <mjrosato@linux.ibm.com>, Thomas Huth <thuth@redhat.com>, David Hildenbrand <david@redhat.com>, Ilya Leoshkevich <iii@linux.ibm.com>, Stefan Hajnoczi <stefanha@redhat.com>, Fam Zheng <fam@euphon.net>

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[PULL 07/28] target/i386: Fix CR2 handling for non-canonical addresses

Posted by Paolo Bonzini 1 month ago

From: Mathias Krause <minipli@grsecurity.net>

Commit 3563362ddfae ("target/i386: Introduce structures for mmu_translate")
accidentally modified CR2 for non-canonical address exceptions while these
should lead to a #GP / #SS instead -- without changing CR2.

Fix that.

A KUT test for this was submitted as [1].

[1] https://lore.kernel.org/kvm/20250612141637.131314-1-minipli@grsecurity.net/

Fixes: 3563362ddfae ("target/i386: Introduce structures for mmu_translate")
Signed-off-by: Mathias Krause <minipli@grsecurity.net>
Link: https://lore.kernel.org/r/20250612142155.132175-1-minipli@grsecurity.net
Cc: qemu-stable@nongnu.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 target/i386/tcg/system/excp_helper.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/target/i386/tcg/system/excp_helper.c b/target/i386/tcg/system/excp_helper.c
index 50040f6fcaf..f622b5d588e 100644
--- a/target/i386/tcg/system/excp_helper.c
+++ b/target/i386/tcg/system/excp_helper.c
@@ -592,7 +592,8 @@ static bool get_physical_address(CPUX86State *env, vaddr addr,
                 if (sext != 0 && sext != -1) {
                     *err = (TranslateFault){
                         .exception_index = EXCP0D_GPF,
-                        .cr2 = addr,
+                        /* non-canonical #GP doesn't change CR2 */
+                        .cr2 = env->cr[2],
                     };
                     return false;
                 }
-- 
2.51.0