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| author |   James Morse <james.morse@arm.com> | 2019-06-18 16:17:36 +0100 |
|---|---|---|
| committer |   Marc Zyngier <marc.zyngier@arm.com> | 2019-07-05 13:03:29 +0100 |
| commit | 0e5b9c085dcef61163f3f277964c1a1623043f67 (patch) | |
| tree | 703a97a9a895dd5829f89ef5fbb5872ae8e690b0 /arch/arm64/kvm/hyp/entry.S | |
| parent | KVM: arm64: Make indirect vectors preamble behaviour symmetric (diff) | |
| download | linux-dev-0e5b9c085dcef61163f3f277964c1a1623043f67.tar.xz linux-dev-0e5b9c085dcef61163f3f277964c1a1623043f67.zip | |
KVM: arm64: Consume pending SError as early as possible
On systems with v8.2 we switch the 'vaxorcism' of guest SError with an
alternative sequence that uses the ESB-instruction, then reads DISR_EL1.
This saves the unmasking and remasking of asynchronous exceptions.
We do this after we've saved the guest registers and restored the
host's. Any SError that becomes pending due to this will be accounted
to the guest, when it actually occurred during host-execution.
Move the ESB-instruction as early as possible. Any guest SError
will become pending due to this ESB-instruction and then consumed to
DISR_EL1 before the host touches anything.
This lets us account for host/guest SError precisely on the guest
exit exception boundary.
Because the ESB-instruction now lands in the preamble section of
the vectors, we need to add it to the unpatched indirect vectors
too, and to any sequence that may be patched in over the top.
The ESB-instruction always lives in the head of the vectors,
to be before any memory write. Whereas the register-store always
lives in the tail.
Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Diffstat (limited to 'arch/arm64/kvm/hyp/entry.S')
| -rw-r--r-- | arch/arm64/kvm/hyp/entry.S | 5 |
1 files changed, 2 insertions, 3 deletions
diff --git a/arch/arm64/kvm/hyp/entry.S b/arch/arm64/kvm/hyp/entry.S index bd34016354ba..fb2e218ce0c7 100644 --- a/arch/arm64/kvm/hyp/entry.S +++ b/arch/arm64/kvm/hyp/entry.S @@ -127,8 +127,8 @@ ENTRY(__guest_exit) alternative_if ARM64_HAS_RAS_EXTN // If we have the RAS extensions we can consume a pending error - // without an unmask-SError and isb. - esb + // without an unmask-SError and isb. The ESB-instruction consumed any + // pending guest error when we took the exception from the guest. mrs_s x2, SYS_DISR_EL1 str x2, [x1, #(VCPU_FAULT_DISR - VCPU_CONTEXT)] cbz x2, 1f @@ -146,7 +146,6 @@ alternative_else mov x5, x0 dsb sy // Synchronize against in-flight ld/st - nop msr daifclr, #4 // Unmask aborts alternative_endif |