On Sat, 11 Jan 2020 at 15:49, Greg Kroah-Hartman gregkh@linuxfoundation.org wrote:
From: Marc Zyngier marc.zyngier@arm.com
commit d3ec3a08fa700c8b46abb137dce4e2514a6f9668 upstream.
In order to workaround the TX2-219 erratum, it is necessary to trap TTBRx_EL1 accesses to EL2. This is done by setting HCR_EL2.TVM on guest entry, which has the side effect of trapping all the other VM-related sysregs as well.
To minimize the overhead, a fast path is used so that we don't have to go all the way back to the main sysreg handling code, unless the rest of the hypervisor expects to see these accesses.
Cc: stable@vger.kernel.org Signed-off-by: Marc Zyngier marc.zyngier@arm.com Signed-off-by: Will Deacon will@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
On stable-rc 4.19 all arm64 builds failed due to this error,
arch/arm64/kvm/hyp/switch.c: In function 'handle_tx2_tvm': arch/arm64/kvm/hyp/switch.c:438:2: error: implicit declaration of function '__kvm_skip_instr'; did you mean 'kvm_skip_instr'? [-Werror=implicit-function-declaration] __kvm_skip_instr(vcpu); ^~~~~~~~~~~~~~~~ kvm_skip_instr cc1: some warnings being treated as errors scripts/Makefile.build:303: recipe for target 'arch/arm64/kvm/hyp/switch.o' failed
Full build log, https://ci.linaro.org/view/lkft/job/openembedded-lkft-linux-stable-rc-4.19/D...