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powerpc/64s/exception: KVM Fix for host DSI being taken in HPT guest MMU context 

Commit 2284ffea8f ("powerpc/64s/exception: Only test KVM in SRR
interrupts when PR KVM is supported") removed KVM guest tests from
interrupts that do not set HV=1, when PR-KVM is not configured.

This is wrong for HV-KVM HPT guest MMIO emulation case which attempts
to load the faulting instruction word with MSR[DR]=1 and MSR[HV]=1 with
the guest MMU context loaded. This can cause host DSI, DSLB interrupts
which must test for KVM guest. Restore this and add a comment.

Fixes: 2284ffea8f ("powerpc/64s/exception: Only test KVM in SRR interrupts when PR KVM is supported")
Cc: stable@vger.kernel.org # v5.7+
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20201117135617.3521127-1-npiggin@gmail.com
This commit is contained in:
Nicholas Piggin 2020-11-17 23:56:17 +10:00 committed by Michael Ellerman
parent e02152ba28
commit cd81acc600
1 changed files with 7 additions and 4 deletions
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11
arch/powerpc/kernel/exceptions-64s.S
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@ -1410,6 +1410,11 @@ END_FTR_SECTION_IFSET(CPU_FTR_HVMODE)
* If none is found, do a Linux page fault. Linux page faults can happen in
* kernel mode due to user copy operations of course.
*
* KVM: The KVM HDSI handler may perform a load with MSR[DR]=1 in guest
* MMU context, which may cause a DSI in the host, which must go to the
* KVM handler. MSR[IR] is not enabled, so the real-mode handler will
* always be used regardless of AIL setting.
*
* - Radix MMU
* The hardware loads from the Linux page table directly, so a fault goes
* immediately to Linux page fault.
@ -1420,10 +1425,8 @@ INT_DEFINE_BEGIN(data_access)
IVEC=0x300
IDAR=1
IDSISR=1
#ifdef CONFIG_KVM_BOOK3S_PR_POSSIBLE
IKVM_SKIP=1
IKVM_REAL=1
#endif
INT_DEFINE_END(data_access)
EXC_REAL_BEGIN(data_access, 0x300, 0x80)
@ -1462,6 +1465,8 @@ ALT_MMU_FTR_SECTION_END_IFCLR(MMU_FTR_TYPE_RADIX)
* ppc64_bolted_size (first segment). The kernel handler must avoid stomping
* on user-handler data structures.
*
* KVM: Same as 0x300, DSLB must test for KVM guest.
*
* A dedicated save area EXSLB is used (XXX: but it actually need not be
* these days, we could use EXGEN).
*/
@ -1470,10 +1475,8 @@ INT_DEFINE_BEGIN(data_access_slb)
IAREA=PACA_EXSLB
IRECONCILE=0
IDAR=1
#ifdef CONFIG_KVM_BOOK3S_PR_POSSIBLE
IKVM_SKIP=1
IKVM_REAL=1
#endif
INT_DEFINE_END(data_access_slb)
EXC_REAL_BEGIN(data_access_slb, 0x380, 0x80)