From: Michael Ellerman <mpe@ellerman.id.au> stable inclusion form stable-v5.10.82 commit a8230fb74b5452b59ed9bd26c6f51ad7e3706982 bugzilla: 185877 https://gitee.com/openeuler/kernel/issues/I4QU6V Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... -------------------------------- [ Upstream commit dae581864609d36fb58855fd59880b4941ce9d14 ] kvmppc_h_set_dabr(), and kvmppc_h_set_xdabr() which jumps into it, need to use _GLOBAL_TOC to setup the kernel TOC pointer, because kvmppc_h_set_dabr() uses LOAD_REG_ADDR() to load dawr_force_enable. When called from hcall_try_real_mode() we have the kernel TOC in r2, established near the start of kvmppc_interrupt_hv(), so there is no issue. But they can also be called from kvmppc_pseries_do_hcall() which is module code, so the access ends up happening with the kvm-hv module's r2, which will not point at dawr_force_enable and could even cause a fault. With the current code layout and compilers we haven't observed a fault in practice, the load hits somewhere in kvm-hv.ko and silently returns some bogus value. Note that we we expect p8/p9 guests to use the DAWR, but SLOF uses h_set_dabr() to test if sc1 works correctly, see SLOF's lib/libhvcall/brokensc1.c. Fixes: c1fe190c0672 ("powerpc: Add force enable of DAWR on P9 option") Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Reviewed-by: Daniel Axtens <dja@axtens.net> Link: https://lore.kernel.org/r/20210923151031.72408-1-mpe@ellerman.id.au Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Chen Jun <chenjun102@huawei.com> Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com> --- arch/powerpc/kvm/book3s_hv_rmhandlers.S | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/powerpc/kvm/book3s_hv_rmhandlers.S b/arch/powerpc/kvm/book3s_hv_rmhandlers.S index db78123166a8..b1d9afffd841 100644 --- a/arch/powerpc/kvm/book3s_hv_rmhandlers.S +++ b/arch/powerpc/kvm/book3s_hv_rmhandlers.S @@ -2539,7 +2539,7 @@ hcall_real_table: .globl hcall_real_table_end hcall_real_table_end: -_GLOBAL(kvmppc_h_set_xdabr) +_GLOBAL_TOC(kvmppc_h_set_xdabr) EXPORT_SYMBOL_GPL(kvmppc_h_set_xdabr) andi. r0, r5, DABRX_USER | DABRX_KERNEL beq 6f @@ -2549,7 +2549,7 @@ EXPORT_SYMBOL_GPL(kvmppc_h_set_xdabr) 6: li r3, H_PARAMETER blr -_GLOBAL(kvmppc_h_set_dabr) +_GLOBAL_TOC(kvmppc_h_set_dabr) EXPORT_SYMBOL_GPL(kvmppc_h_set_dabr) li r5, DABRX_USER | DABRX_KERNEL 3: -- 2.20.1