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| author | Michael Ellerman <mpe@ellerman.id.au> | 2021-09-23 18:10:31 +0300 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2021-11-15 07:46:45 +0300 |
| commit | dae581864609d36fb58855fd59880b4941ce9d14 (patch) | |
| tree | 80fc0c485a1c4f79e8b154e9fcff81d6adf7f51e /arch/powerpc/kvm | |
| parent | 158ea2d2b2ff8fb49f39209a31b4920f13193a3d (diff) | |
| download | linux-dae581864609d36fb58855fd59880b4941ce9d14.tar.xz | |
KVM: PPC: Book3S HV: Use GLOBAL_TOC for kvmppc_h_set_dabr/xdabr()
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
Diffstat (limited to 'arch/powerpc/kvm')
| -rw-r--r-- | arch/powerpc/kvm/book3s_hv_rmhandlers.S | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/arch/powerpc/kvm/book3s_hv_rmhandlers.S b/arch/powerpc/kvm/book3s_hv_rmhandlers.S index eb776d0c5d8e..32a4b4d412b9 100644 --- a/arch/powerpc/kvm/book3s_hv_rmhandlers.S +++ b/arch/powerpc/kvm/book3s_hv_rmhandlers.S @@ -2005,7 +2005,7 @@ 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 @@ -2015,7 +2015,7 @@ 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: |