From: Colin Xu <colin.xu@xxxxxxxxx> commit 8fe105679765700378eb328495fcfe1566cdbbd0 upstream If guest fills non-priv bb on ApolloLake/Broxton as Mesa i965 does in: 717e7539124d (i965: Use a WC map and memcpy for the batch instead of pw-) Due to the missing flush of bb filled by VM vCPU, host GPU hangs on executing these MI_BATCH_BUFFER. Temporarily workaround this by setting SNOOP bit for PAT3 used by PPGTT PML4 PTE: PAT(0) PCD(1) PWT(1). The performance is still expected to be low, will need further improvement. Acked-by: Zhenyu Wang <zhenyuw@xxxxxxxxxxxxxxx> Signed-off-by: Colin Xu <colin.xu@xxxxxxxxx> Signed-off-by: Zhenyu Wang <zhenyuw@xxxxxxxxxxxxxxx> Link: http://patchwork.freedesktop.org/patch/msgid/20201012045231.226748-1-colin.xu@xxxxxxxxx (cherry picked from commit 8fe105679765700378eb328495fcfe1566cdbbd0) Signed-off-by: Colin Xu <colin.xu@xxxxxxxxx> Cc: <stable@xxxxxxxxxxxxxxx> # 5.4.y Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/gpu/drm/i915/gvt/handlers.c | 32 +++++++++++++++++++++++++++++++- 1 file changed, 31 insertions(+), 1 deletion(-) --- a/drivers/gpu/drm/i915/gvt/handlers.c +++ b/drivers/gpu/drm/i915/gvt/handlers.c @@ -1632,6 +1632,34 @@ static int edp_psr_imr_iir_write(struct return 0; } +/** + * FixMe: + * If guest fills non-priv batch buffer on ApolloLake/Broxton as Mesa i965 did: + * 717e7539124d (i965: Use a WC map and memcpy for the batch instead of pwrite.) + * Due to the missing flush of bb filled by VM vCPU, host GPU hangs on executing + * these MI_BATCH_BUFFER. + * Temporarily workaround this by setting SNOOP bit for PAT3 used by PPGTT + * PML4 PTE: PAT(0) PCD(1) PWT(1). + * The performance is still expected to be low, will need further improvement. + */ +static int bxt_ppat_low_write(struct intel_vgpu *vgpu, unsigned int offset, + void *p_data, unsigned int bytes) +{ + u64 pat = + GEN8_PPAT(0, CHV_PPAT_SNOOP) | + GEN8_PPAT(1, 0) | + GEN8_PPAT(2, 0) | + GEN8_PPAT(3, CHV_PPAT_SNOOP) | + GEN8_PPAT(4, CHV_PPAT_SNOOP) | + GEN8_PPAT(5, CHV_PPAT_SNOOP) | + GEN8_PPAT(6, CHV_PPAT_SNOOP) | + GEN8_PPAT(7, CHV_PPAT_SNOOP); + + vgpu_vreg(vgpu, offset) = lower_32_bits(pat); + + return 0; +} + static int mmio_read_from_hw(struct intel_vgpu *vgpu, unsigned int offset, void *p_data, unsigned int bytes) { @@ -2778,7 +2806,7 @@ static int init_broadwell_mmio_info(stru MMIO_DH(GEN6_PCODE_MAILBOX, D_BDW_PLUS, NULL, mailbox_write); - MMIO_D(GEN8_PRIVATE_PAT_LO, D_BDW_PLUS); + MMIO_D(GEN8_PRIVATE_PAT_LO, D_BDW_PLUS & ~D_BXT); MMIO_D(GEN8_PRIVATE_PAT_HI, D_BDW_PLUS); MMIO_D(GAMTARBMODE, D_BDW_PLUS); @@ -3281,6 +3309,8 @@ static int init_bxt_mmio_info(struct int MMIO_DFH(GEN9_CTX_PREEMPT_REG, D_BXT, F_CMD_ACCESS, NULL, NULL); + MMIO_DH(GEN8_PRIVATE_PAT_LO, D_BXT, NULL, bxt_ppat_low_write); + return 0; }
