From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Eric Farman Subject: [PATCH v3 3/3] s390/cio: Remove vfio-ccw checks of command codes Date: Thu, 16 May 2019 18:14:03 +0200 In-Reply-To: <20190516161403.79053-1-farman@linux.ibm.com> References: <20190516161403.79053-1-farman@linux.ibm.com> Message-Id: <20190516161403.79053-4-farman@linux.ibm.com> Sender: kvm-owner@vger.kernel.org List-Archive: List-Post: To: Cornelia Huck , Farhan Ali Cc: Halil Pasic , Pierre Morel , linux-s390@vger.kernel.org, kvm@vger.kernel.org, Eric Farman List-ID: If the CCW being processed is a No-Operation, then by definition no data is being transferred. Let's fold those checks into the normal CCW processors, rather than skipping out early. Likewise, if the CCW being processed is a "test" (a category defined here as an opcode that contains zero in the lowest four bits) then no special processing is necessary as far as vfio-ccw is concerned. These command codes have not been valid since the S/370 days, meaning they are invalid in the same way as one that ends in an eight [1] or an otherwise valid command code that is undefined for the device type in question. Considering that, let's just process "test" CCWs like any other CCW, and send everything to the hardware. [1] POPS states that a x08 is a TIC CCW, and that having any high-order bits enabled is invalid for format-1 CCWs. For format-0 CCWs, the high-order bits are ignored. Signed-off-by: Eric Farman --- drivers/s390/cio/vfio_ccw_cp.c | 11 +++++------ 1 file changed, 5 insertions(+), 6 deletions(-) diff --git a/drivers/s390/cio/vfio_ccw_cp.c b/drivers/s390/cio/vfio_ccw_cp.c index c77c9b4cd2a8..f73cfcfdd032 100644 --- a/drivers/s390/cio/vfio_ccw_cp.c +++ b/drivers/s390/cio/vfio_ccw_cp.c @@ -295,8 +295,6 @@ static long copy_ccw_from_iova(struct channel_program *cp, #define ccw_is_read_backward(_ccw) (((_ccw)->cmd_code & 0x0F) == 0x0C) #define ccw_is_sense(_ccw) (((_ccw)->cmd_code & 0x0F) == CCW_CMD_BASIC_SENSE) -#define ccw_is_test(_ccw) (((_ccw)->cmd_code & 0x0F) == 0) - #define ccw_is_noop(_ccw) ((_ccw)->cmd_code == CCW_CMD_NOOP) #define ccw_is_tic(_ccw) ((_ccw)->cmd_code == CCW_CMD_TIC) @@ -320,6 +318,10 @@ static inline int ccw_does_data_transfer(struct ccw1 *ccw) if (ccw->count == 0) return 0; + /* If the command is a NOP, then no data will be transferred */ + if (ccw_is_noop(ccw)) + return 0; + /* If the skip flag is off, then data will be transferred */ if (!ccw_is_skip(ccw)) return 1; @@ -404,7 +406,7 @@ static void ccwchain_cda_free(struct ccwchain *chain, int idx) { struct ccw1 *ccw = chain->ch_ccw + idx; - if (ccw_is_test(ccw) || ccw_is_noop(ccw) || ccw_is_tic(ccw)) + if (ccw_is_tic(ccw)) return; kfree((void *)(u64)ccw->cda); @@ -730,9 +732,6 @@ static int ccwchain_fetch_one(struct ccwchain *chain, { struct ccw1 *ccw = chain->ch_ccw + idx; - if (ccw_is_test(ccw) || ccw_is_noop(ccw)) - return 0; - if (ccw_is_tic(ccw)) return ccwchain_fetch_tic(chain, idx, cp); -- 2.17.1