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| author | Ard Biesheuvel <ardb@kernel.org> | 2024-10-09 18:04:40 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2025-04-25 10:44:01 +0200 |
| commit | 32e3456454402967c6ee91074a26dc17bca465cb (patch) | |
| tree | b491be0e89b8200eff0764892be78e09dde51e77 | |
| parent | 8dfff85d5d7cd616aaeb9cd57c8cda9476e868fe (diff) | |
| download | linux-32e3456454402967c6ee91074a26dc17bca465cb.tar.gz linux-32e3456454402967c6ee91074a26dc17bca465cb.tar.bz2 linux-32e3456454402967c6ee91074a26dc17bca465cb.zip | |
x86/pvh: Call C code via the kernel virtual mapping
commit e8fbc0d9cab6c1ee6403f42c0991b0c1d5dbc092 upstream.
Calling C code via a different mapping than it was linked at is
problematic, because the compiler assumes that RIP-relative and absolute
symbol references are interchangeable. GCC in particular may use
RIP-relative per-CPU variable references even when not using -fpic.
So call xen_prepare_pvh() via its kernel virtual mapping on x86_64, so
that those RIP-relative references produce the correct values. This
matches the pre-existing behavior for i386, which also invokes
xen_prepare_pvh() via the kernel virtual mapping before invoking
startup_32 with paging disabled again.
Fixes: 7243b93345f7 ("xen/pvh: Bootstrap PVH guest")
Tested-by: Jason Andryuk <jason.andryuk@amd.com>
Reviewed-by: Jason Andryuk <jason.andryuk@amd.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Message-ID: <20241009160438.3884381-8-ardb+git@google.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
[ Stable context update ]
Signed-off-by: Jason Andryuk <jason.andryuk@amd.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | arch/x86/platform/pvh/head.S | 7 |
1 files changed, 6 insertions, 1 deletions
diff --git a/arch/x86/platform/pvh/head.S b/arch/x86/platform/pvh/head.S index 7fe564eaf228..9e6a27018d0f 100644 --- a/arch/x86/platform/pvh/head.S +++ b/arch/x86/platform/pvh/head.S @@ -100,7 +100,12 @@ SYM_CODE_START_LOCAL(pvh_start_xen) xor %edx, %edx wrmsr - call xen_prepare_pvh + /* Call xen_prepare_pvh() via the kernel virtual mapping */ + leaq xen_prepare_pvh(%rip), %rax + subq phys_base(%rip), %rax + addq $__START_KERNEL_map, %rax + ANNOTATE_RETPOLINE_SAFE + call *%rax /* startup_64 expects boot_params in %rsi. */ mov $_pa(pvh_bootparams), %rsi |