From 29b500b54ef379f1f3227b633dd477a4dd3cd62b Mon Sep 17 00:00:00 2001 From: James Hogan Date: Fri, 11 Nov 2016 14:08:32 +0000 Subject: [PATCH] KVM: MIPS: Support NetLogic KScratch registers MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit tlbex.c uses the implementation dependent $22 CP0 register group on NetLogic cores, with the help of the c0_kscratch() helper. Allow these registers to be allocated by the KVM entry code too instead of assuming KScratch registers are all $31, which will also allow pgd_reg to be handled since it is allocated that way. We also drop the masking of kscratch_mask with 0xfc, as it is redundant for the standard KScratch registers (Config4.KScrExist won't have the low 2 bits set anyway), and apparently not necessary for NetLogic. Signed-off-by: James Hogan Cc: Paolo Bonzini Cc: "Radim Krčmář" Cc: Ralf Baechle Cc: linux-mips@linux-mips.org Cc: kvm@vger.kernel.org --- arch/mips/kvm/entry.c | 25 ++++++++++++++++++++----- 1 file changed, 20 insertions(+), 5 deletions(-) diff --git a/arch/mips/kvm/entry.c b/arch/mips/kvm/entry.c index f683d123172c..7424d3d566ff 100644 --- a/arch/mips/kvm/entry.c +++ b/arch/mips/kvm/entry.c @@ -91,6 +91,21 @@ static void *kvm_mips_build_ret_from_exit(void *addr); static void *kvm_mips_build_ret_to_guest(void *addr); static void *kvm_mips_build_ret_to_host(void *addr); +/* + * The version of this function in tlbex.c uses current_cpu_type(), but for KVM + * we assume symmetry. + */ +static int c0_kscratch(void) +{ + switch (boot_cpu_type()) { + case CPU_XLP: + case CPU_XLR: + return 22; + default: + return 31; + } +} + /** * kvm_mips_entry_setup() - Perform global setup for entry code. * @@ -105,18 +120,18 @@ int kvm_mips_entry_setup(void) * We prefer to use KScratchN registers if they are available over the * defaults above, which may not work on all cores. */ - unsigned int kscratch_mask = cpu_data[0].kscratch_mask & 0xfc; + unsigned int kscratch_mask = cpu_data[0].kscratch_mask; /* Pick a scratch register for storing VCPU */ if (kscratch_mask) { - scratch_vcpu[0] = 31; + scratch_vcpu[0] = c0_kscratch(); scratch_vcpu[1] = ffs(kscratch_mask) - 1; kscratch_mask &= ~BIT(scratch_vcpu[1]); } /* Pick a scratch register to use as a temp for saving state */ if (kscratch_mask) { - scratch_tmp[0] = 31; + scratch_tmp[0] = c0_kscratch(); scratch_tmp[1] = ffs(kscratch_mask) - 1; kscratch_mask &= ~BIT(scratch_tmp[1]); } @@ -132,7 +147,7 @@ static void kvm_mips_build_save_scratch(u32 **p, unsigned int tmp, UASM_i_SW(p, tmp, offsetof(struct pt_regs, cp0_epc), frame); /* Save the temp scratch register value in cp0_cause of stack frame */ - if (scratch_tmp[0] == 31) { + if (scratch_tmp[0] == c0_kscratch()) { UASM_i_MFC0(p, tmp, scratch_tmp[0], scratch_tmp[1]); UASM_i_SW(p, tmp, offsetof(struct pt_regs, cp0_cause), frame); } @@ -148,7 +163,7 @@ static void kvm_mips_build_restore_scratch(u32 **p, unsigned int tmp, UASM_i_LW(p, tmp, offsetof(struct pt_regs, cp0_epc), frame); UASM_i_MTC0(p, tmp, scratch_vcpu[0], scratch_vcpu[1]); - if (scratch_tmp[0] == 31) { + if (scratch_tmp[0] == c0_kscratch()) { UASM_i_LW(p, tmp, offsetof(struct pt_regs, cp0_cause), frame); UASM_i_MTC0(p, tmp, scratch_tmp[0], scratch_tmp[1]); } -- 2.20.1