From 0ace3d3b70ed6a474d52fc44ee9b0b1f16ca3724 Mon Sep 17 00:00:00 2001 From: Niklas Cassel Date: Fri, 22 Mar 2024 17:41:38 +0100 Subject: misc: pci_endpoint_test: Use memcpy_toio()/memcpy_fromio() for BAR tests MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The current code uses writel()/readl(), which has an implicit memory barrier for every single readl()/writel(). Additionally, reading 4 bytes at a time over the PCI bus is not really optimal, considering that this code is running in an ioctl handler. Use memcpy_toio()/memcpy_fromio() for BAR tests. Before patch with a 4MB BAR: $ time /usr/bin/pcitest -b 1 BAR1: OKAY real 0m 1.56s After patch with a 4MB BAR: $ time /usr/bin/pcitest -b 1 BAR1: OKAY real 0m 0.54s Link: https://lore.kernel.org/linux-pci/20240322164139.678228-1-cassel@kernel.org Signed-off-by: Niklas Cassel Signed-off-by: Krzysztof Wilczyński Signed-off-by: Bjorn Helgaas Reviewed-by: Manivannan Sadhasivam Reviewed-by: Kuppuswamy Sathyanarayanan --- drivers/misc/pci_endpoint_test.c | 54 +++++++++++++++++++++++++++++++--------- 1 file changed, 42 insertions(+), 12 deletions(-) (limited to 'drivers/misc') diff --git a/drivers/misc/pci_endpoint_test.c b/drivers/misc/pci_endpoint_test.c index 56ac6969a8f5..4f3ec1f2ba9f 100644 --- a/drivers/misc/pci_endpoint_test.c +++ b/drivers/misc/pci_endpoint_test.c @@ -7,6 +7,7 @@ */ #include +#include #include #include #include @@ -272,31 +273,60 @@ static const u32 bar_test_pattern[] = { 0xA5A5A5A5, }; +static int pci_endpoint_test_bar_memcmp(struct pci_endpoint_test *test, + enum pci_barno barno, int offset, + void *write_buf, void *read_buf, + int size) +{ + memset(write_buf, bar_test_pattern[barno], size); + memcpy_toio(test->bar[barno] + offset, write_buf, size); + + memcpy_fromio(read_buf, test->bar[barno] + offset, size); + + return memcmp(write_buf, read_buf, size); +} + static bool pci_endpoint_test_bar(struct pci_endpoint_test *test, enum pci_barno barno) { - int j; - u32 val; - int size; + int j, bar_size, buf_size, iters, remain; + void *write_buf __free(kfree) = NULL; + void *read_buf __free(kfree) = NULL; struct pci_dev *pdev = test->pdev; if (!test->bar[barno]) return false; - size = pci_resource_len(pdev, barno); + bar_size = pci_resource_len(pdev, barno); if (barno == test->test_reg_bar) - size = 0x4; + bar_size = 0x4; - for (j = 0; j < size; j += 4) - pci_endpoint_test_bar_writel(test, barno, j, - bar_test_pattern[barno]); + /* + * Allocate a buffer of max size 1MB, and reuse that buffer while + * iterating over the whole BAR size (which might be much larger). + */ + buf_size = min(SZ_1M, bar_size); - for (j = 0; j < size; j += 4) { - val = pci_endpoint_test_bar_readl(test, barno, j); - if (val != bar_test_pattern[barno]) + write_buf = kmalloc(buf_size, GFP_KERNEL); + if (!write_buf) + return false; + + read_buf = kmalloc(buf_size, GFP_KERNEL); + if (!read_buf) + return false; + + iters = bar_size / buf_size; + for (j = 0; j < iters; j++) + if (pci_endpoint_test_bar_memcmp(test, barno, buf_size * j, + write_buf, read_buf, buf_size)) + return false; + + remain = bar_size % buf_size; + if (remain) + if (pci_endpoint_test_bar_memcmp(test, barno, buf_size * iters, + write_buf, read_buf, remain)) return false; - } return true; } -- cgit v1.2.3